Perth Veterinary Oncology

The specialty of Oncology is concerned with the diagnosis of cancers and providing the best care for patients with cancer. There are many ways we help pets with cancer, with most focus on quality of life. Medication, surgery, radiation, diet and home therapy can all have a place in caring for pets with cancer. Some medications are best given in hospital, others can be readily given at home.

The first step is a full assessment so that we can work out if more information is needed and what treatment options are most appropriate. We recommend allowing up to an hour for the first consultation.

Cancer Vaccine Trial – RECRUITING  CASES NOW


Recently we completed the first phase of a world-first cancer treatment research trial. In conjunction with Curtin University, a vaccine has been developed with the potential to direct the immune system to destroy cancer. Given the success from phase one, we have now secured funding to begin phase two. If you have a dog with cancer and are interested in considering joining this trial the important points are:
  1. Your dog MUST have a tumour on the OUTSIDE of the body (visible in the mouth is acceptable).
  2. The tumour must be suspected or proven to be a soft tissue sarcoma. (Final tests to confirm this can be done by us at no cost to you).
  3. There must be a visible lump (meaning this treatment is not used after the tumour has been removed).
  4. You must be able to leave your dog with us on Monday, Wednesday and Friday for 2 consecutive weeks, and return weekly then monthly for a year. All visits and treatments must be at Perth Veterinary Specialists.
  5. The tumour must not have been treated with chemotherapy or radiation therapy before.
  6. The trial is fully funded, meaning there are no costs for you to cover.
  7. To enter the trial, a blood sample will be collected and tested by Curtin University. ONLY if your dog’s blood reacts to the vaccine will your dog be permitted in the trial.
  8. There are currently 6 spots available. This is limited by the amount of vaccine that has been produced and therefore cannot be extended at present.
  9. This trial has been reviewed and accepted by the Curtin University Animal Ethics Committee.
  10. If you believe your dog may be suitable, please contact us by email only. At the bottom of this page, you can click on the domain name address next to ‘email’. Please write ‘Cancer Vaccine Trial’ in the head of the email.


Components of food with importance to human cancer incidence

Substance Causes Cancer Prevents cancer
Meat: animal fat Breast, colon, prostate
Cooked meat: heterocyclic aromatic amines Liver, colon, breast, prostate, lymphoid, oral cavity, lung
Cooked meat: heterocyclic aromatic amines Liver, colon, breast, prostate, lymphoid, oral cavity, lung
Cooked or smoked meat: polycyclic aromatic hydrocarbons Similar compounds to cigarette smoke and industrial pollutants
Cooked or smoked meat: N-nitrosocompounds Nasopharygeal, bladder, liver
Fruits & veges: Carotenoids Prostate, lung, stomach
Fruits & grains: phytoestrogens Breast, colon & prostate
Veges: organosulfurs Gastric
Fruit & veges: phenolics Ovarian, breast, stomach, melanoma
Citrus fruit: monoterpenes Breast, skin, liver, lung, pancreas, prostate
Veges: Isothiocyanates & indoles Breast, oesophagus, lung
Soy: Protease inhibitors Various
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To follow are notes from a presentation to specialists and general practitioners at the ACVSc annual conference, Gold Coast, 2004


In 1991, Lluis Mir et al reported that some cytotoxic drugs, particularly bleomycin were more toxic when the target cells were electropermeabilised. Bleomycin is unable to enter normal cells by diffusion; rather it gains entry by receptor-mediated endocytosis. Electropermeabilisation, as the name suggests, is able to render a cell permeable, such that bleomycin can enter more easily. The electrical pulses alter the transmembrane potential difference, allowing hydrophilic molecules to enter the cell by diffusion. Charged molecules may enter by electrophoresis during the pulse (100µs) but by convection for a period thereafter. Most studies utilise 8 square wave pulses of 1Hz frequency, 100µs, and 1000 to 1300V/cm. Both external plates and needle electrodes may be used.

The chemotherapy component (most commonly bleomycin or cisplatin) has been administered either as systemic drug therapy or as intralesional injection of drug. The electropermeabilisation is administered around the time of the intralesional treatment, or 8-28 minutes after intravenous injection of bleomycin. Electrochemotherapy holds promise as an alternative to surgical removal of a mass, or as an adjuvant therapy to treat a perisurgical region. In addition, it is becoming popular for the treatment of bleeding cutaneous metastases in people. Other than some pain at the time of the procedure, electrochemotherapy is generally free of adverse effects. As with any local medical treatment, responses are variable.

In one in vitro study, vascular endothelial cells were shown to be highly sensitive to electrochemotherapy suggesting that one of the effects of treatment might be reduced blood flow through the tumour. A second confirmed this effect, documenting maximum reduction at 2 hours and return to normality by 48 hours after treatment. Furthermore, the electrodes used to deliver the electropermeabilisation release ferrous ions in measurable concentration into the tissue and it is therefore possible that some of the clinical effect is due to iron supporting free radical damage.

Randomised studies in both animals and people have consistently shown responses for patients given electrochemotherapy versus those given either intralesional bleomycin or electropermeabilisation alone. In a murine bladder tumour study, bleomycin was found to reach 100 times the concentration within cells following electropermeabilisation when compared to controls. Cisplatin concentration was doubled, and doxorubicin was not preferentially absorbed into cells. A murine leiomyosarcoma study showed bleomycin to reach 10 times the concentration when administered with electropermeabilisation. Importantly, a different study showed that mice with a cisplatin resistant tumour were sensitive when the cisplatin was administered with electropermeabilisation.

There have been several studies using electrochemotherapy on people with a range of skin cancers including melanoma, basal cell carcinoma, salivary and breast cancer metastases. Response rates have generally been high using either bleomycin or cisplatin. In some studies, the procedure has been repeated several times at intervals of approximately 1 week.

Mir published a study in 1997 detailing a group of 12 cats with spontaneous high-grade recurrent soft tissue sarcomas. These cats were given approximately 10U/m2 bleomycin intravenously followed 20 minutes later by electropermeabilisation. The only adverse effects were local inflammation. Whilst only one partial remission was observed, the tumours remained stable for up to 7 months, resulting in significantly longer survival than the 11 control cats. Systemic side effects were not observed mirroring the experiences of an early study utilising bleomycin for SCC in cats.

Histopathologic assessment of tumours entering apparent stable disease has revealed replacement of neoplastic tissue by a fibrocytic response. This cicatricial effect will tend to result in responses being underestimated. The mechanism for a prolonged benefit resulting from electrochemotherapy has not been shown. Whilst the inflammation that promotes the cicatricial response may encourage an immune response against the tumour, it is possible that prolonged periods of stable disease following treatment are in effect partial or complete remission with gradual regrowth that were misclassified due to the absence of marked size reduction due to replacement of tumour by scar.

We have been using electrochemotherapy since February 2003 for patients with small solid tumours, for which surgical treatment was refused. Patients are sedated deeply, including routine use of systemic analgesia and regional blocks where appropriate. The electrochemotherapy procedure is then performed, and the patient discharged generally with a NSAID as pain control.

To date, 14 dogs and 2 cats have been treated, with a range of responses from complete remission to no apparent benefit, with most patients obtaining some size reduction and stable disease. Other than a variable degree of inflammation at the treatment site, there have been no adverse effects documented in our patients. Electrochemotherapy appears to be a promising alternative to the surgical treatment of solid tumours.

Cemazar M et al, Electrochemotherapy of tumours resistant to cisplatin: a study in a murine tumour model, Eur J Cancer 2001; 37(9): 1166-72

Heller R, Treatment of cutaneous and subcutaneous tumors with electrochemotherapy using intralesional bleomycin, Cancer 1998; 83(1): 148-57

Horiuchi A et al, Enhancement of antitumor effect of bleomycin by low-voltage in vivo electroporation a study of human uterine leiomyosarcomas in nude mice, Int J Cancer 2000; 88(4): 640-4

Hyacinthe M et al, Electrically enhanced drug delivery for the treatment of soft tissue sarcoma, Cancer 1999: 85(2): 409-417

Mir LM et al, Electrochemotherapy potentiation of antitumour effect of bleomycin by local electric pulses, Eur J Cancer 1991; 27(1): 68-72

Mir LM et al, First clinical trial of cat soft-tissue sarcomas treatment by electrochemotherapy, Br J Cancer 1997; 76(2): 1617-22

Mir LM, Therapeutic perspectives of in vivo cell electropermeabilization, Bioelectrochemistry 2001; 53(1): 1-10

Rodriguez-Cuevas S et al, Electrochemotherapy in primary and metastatic skin tumours: phase II trial using intralesional bleomycin, Arch Med Res 2001; 32(4): 273-6

Sersa G et al, Electrochemotherapy with cisplatin: clinical experience in malignant melanoma patients, Clin Cancer Res 2000; 6(3): 863-7

Sersa G, Reduced blood flow and oxygenation in SA-1 tumours after electrochemotherapy with cisplatin, Br J Cancer 2002; 87(9): 1047-54

Tomov T & Tsoneva I, Are the stainless steel electrodes inert?, Bioelectrochemistry 2000; 51(2): 207-9

Tozon N, Sersa G, & Cemazar, M, Electrochemotherapy: Potentiation of local antitumour effectiveness of cisplatin in dogs and cats, Anticancer Res 2001; 21:2483-2486

Mir LM et al, First clinical trial of cat soft-tissue sarcomas treatment by electrochemotherapy, Br J Cancer 1997; 76(2): 1617-22

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Drs Ken Wyatt and Amy Lane are Western Australia’s only veterinary oncologists. Owners of pets requiring referral should speak to their usual veterinarians to organise this.

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Palliative Care

The traditional approach to helping patients with terminal diseases used to consist of a combination of active treatment of the disease together with treatment of any problems encountered along the way. At some point, active treatment of the disease would cease and the patient would then receive palliative care purely designed to assist quality of life prior to death, or for many veterinary patients, euthanasia.

This view to medicine has changed to a shared care model, an example of which is shown on this page (from Auret, K. Palliative care and cancer, Cancer Forum, The Cancer Council Australia, p3-5, vol31, 2007).


The World Health Organisation describes palliative care “as an approach that improves the quality of life of patients and their families facing the problem associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial and spiritual. Palliative care:

  • provides relief from pain and other distressing symptoms;
  • affirms life and regards dying as a normal process;
  • intends neither to hasten or postpone death;
  • integrates the psychological and spiritual aspects of patient care;
  • offers a support system to help patients live as actively as possible until death;
  • offers a support system to help the family cope during the patients illness and in their own bereavement;
  • uses a team approach to address the needs of patients and their families, including bereavement counselling, if indicated;
  • will enhance quality of life, and may also positively influence the course of illness;
  • is applicable early in the course of illness, in conjunction with other therapies that are intended to prolong life, such as chemotherapy or radiation therapy, and includes those investigations needed to better understand and manage distressing clinical complications.”

At Perth Veterinary Oncology, we strongly support the shared care model of palliative care, such that the primary objective of treatment for most patients regardless of what types of treatment they receive, is to IMPROVE quality of life.  Medications available for specialist palliative care of people are also available for dogs and cats.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Drs Ken Wyatt and Amy Lane are Western Australia’s only veterinary oncologists. Owners of pets requiring referral should speak to their usual veterinarians to organise this.

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The following is an outline of a talk presented at AVA House to general practitioners on 4th April 2007:

Cryotherapy: why you should be using it more often?
Dr Ken Wyatt BSc BVMS FACVSc
Dr Amy Lane BVSc (Hons)
Perth Veterinary Oncology

What is cryosurgery?
Cryotherapy is any form of low temperature treatment.
Cryosurgery is specifically freezing tissue in order to kill it.
An alternative to surgical removal
Other methods include:
Intralesional chemotherapy

Why you should use it more often?

Sedation and analgesia only
Relatively low level pain easily covered by local anaesthesia and a brief course of NSAIDs
Rapid recovery
Low impact for spot treatment of multiple lesions


Low risk
Relatively low cost
Good success when cases selected appropriately

Mode of action

Main action
Ice crystals form and shear membranes

Other effects
vascular stasis, pH changes, and thermal shock.
Successful  cryosurgery requires that temperatures reach -50° to -60°C
Including deep and lateral margins.
Tissue warms at 10°C per mm

Benign complications

Temporary complications
exudate, oedema.
Rarely, delayed haemorrhage at 2 weeks.

Permanent complications
tissue contraction, hypopigmentation, alopecia and scarring.
Minor slough
Extremities; usually expected as part of treatment, e.g. nasal plane

Serious complications
Slough requiring surgery
when aggressive cryosurgery is used followed by post-treatment trauma
Nitrogen embolus
Necrotic bone fragment

How do you use it?

We use ACP/morphine followed by half induction dose diazepam/ketamine
Minimal clipping of fur

Local anaesthetic
Regional block preferable
If local then ring / circumferential block

Protect local tissues
Clinician skin vs drapes
Inject saline into conjunctiva if required

Debulk first
Allows histopathology if necessary
Allows easier penetration of deeper tissues

Ice ball
The frozen area should be assessed visually rather than manually. Note the ice ball is below 0°C only.
Measure temperature with probes?
Aim for -50°C

Natural thaw
Increases cell kill
Don’t remove the probe if stuck
2-5 cycles dependant on thaw time and degree of malignancy

Liquid nitrogen:
– spray
– probe
Nitrous oxide

Liquid Nitrogen
Lowest temperature = -196degC
Requires a Dewar
Evaporates at 1% per week
Spray freezing – ideal
– faster, deeper, non spherical lesions
Probe freezing
– probe size : lesion size should approach 1:1
Achieves deep freeze

Nitrous Oxide
Lowest temperature = -89°C
Stored in standard tank
– no evaporation
– not used often in general practice GA anymore
Only probe freezing
Only shallow freezing, lesions < 1cm

Coolant mixture of dimethyl ether and propane (DMEP) in aerosol form
Lowest temperature -55°C
– 2mm probe for ~ 90 seconds
– 5mm probe for ~ 120 seconds
Shelf life 2-3 years?

Benign tumours
– meibomian gland adenoma, papilloma, benign       melanoma
Any length of eyelid can be frozen
Maintains near-normal cosmetics and function
– area will repigment over 3-6 months; cilia won’t       regrow
Recurrence rates < 5%

Mainly perianal adenomas
Isolated and defined lesions, <90° of anal circumference
No more than 50% of anus should be frozen to avoid anal stenosis
Shouldn’t require antibiotics
E-collar if excessive licking
Recurrence < 5% (when combined with castration)

Low grade tumours adherent or minimally invasive into one cortex.
Destruction of tumour cells within bone but maintain bony framework
Freeze 3 times with 5mm margin
2-3mm necrotic bone -> sequestrum
Literature provides poor control rates
– largely due to poor case selection

Benign skin tumours very common
Mainly removed for cosmetic, inflammatory or functional reasons
May produce white hair on the periphery and small areas of hairless epithelium in the centre

Cases to avoid – absolute
Treatment size beyond the depth of the equipment.
Tumours that have already been frozen once, unless
technical aspects allow more success
E.g. spray vs probe
Recurrence is clearly at lateral margin
When margin assessment is required

Cases to avoid – Relative
Raw bone

Mast cell tumours
Inflammation after treatment

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Drs Ken Wyatt and Amy Lane are Western Australia’s only veterinary oncologists. Owners of pets requiring referral should speak to their usual veterinarians to organise this.

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One of the most common oncology enquiries relates to which tumours can be treated by chemotherapy. It is difficult to generalise as almost any cancer patient can benefit from referral. For many patients, chemotherapy will be appropriate, whilst for others immunostimulant treatments, disease-specific analgesia, anti-angiogenic therapy, nutritional advice or local therapies (cryotherapy, intralesional chemotherapy, electrochemotherapy) will serve the patient best. Although the name and grading of the tumour are important factors in making this decision, the patient and owner are obviously vital considerations. We therefore prefer that patients present for assessment rather than ‘for treatment’, as owners may become disappointed if treatment is different to, or less appropriate than a primary care veterinarian has suggested. Secondly, treatment options can change rapidly. For example, malignant histiocytosis and canine oral squamous cell carcinoma have been recently recognised as chemo-responsive in some cases, but this information does not yet appear in any oncology texts.

There are many ways to help dogs and cats with cancer. Paramount in every case is keeping quality of life good and this is usually easiest to achieve if the amount of cancer in the body is reduced. This can be done with surgery, radiation, and medical treatments. Proven medical therapies for pets with cancer are of 4 broad types. These treatments are specific to the cancer type and not every cancer can be treated effectively with medicine.

One approach uses medications given by drip, injection, or by mouth every 1-4 weeks, usually for 2-6 months.  Whilst the drugs differ depending on the cancer, they are only used if the effective dose can be given without side effects to the majority of patients. Those that do prove sensitive can often still be treated effectively with lower doses. These treatments are given in hospital but in most cases only require a half day to be administered safely.

Another category of treatment is termed metronomic therapy. This requires frequent (every 1-2 days) medication and is simply the use of tablets at home. Some of these treatments work directly on the cancer, but all work on the tissue the cancer grows in as well. By lifting the ability of the immune system to ‘see’ the tumour, and limiting the ability of the cancer to acquire new blood vessels, the growth of the tumours can in many cases be dramatically slowed.

When the focus is on a specific site in the body (i.e. a single tumour rather than widespread cancer), drugs can often be injected into the tumour effectively. These procedures carry no risk of sickness.

Finally, vaccines are being developed to harness the immune system to fight cancer. At present, there is only one vaccine available (for melanoma in dogs), but hopefully this method will allow more options in time.

Every patient and every cancer is unique, and the best option will vary in each case. Your veterinarian can refer you to Perth Veterinary Oncology if you would like more information concerning all options for your pet.

Answers to other common questions include:

  1. Toxicity is low for all protocols. Less than 5% of patients require hospitalisation, and usually less than 30% report any side effects at all. Most animals therefore remain side-effect-free throughout treatment. Occupational exposure and chronic toxicity risk with exposure to cytotoxic drugs should be a serious concern to veterianarians; PVO operates to Australian Standards for a human oncology unit and complies with all legislation including the use of BOTH a cytotoxic suite AND needleless drug preparation. Without the precautions that we take, the use of cytotoxic drugs has been proven to cause organ disease, cancer and birth defects, most notably in nursing staff.
  2. Length of treatment is highly variable and protocol-dependent. The majority of patients will receive from 1 to 16 treatments over 1 to 6 months. Tumours being treated by electrochemotherapy can respond well to a single treatment. Patients on anti-angiogenic therapy may enjoy significant delay in tumour recurrence, but may be on medication for life.
  3. Costs also are difficult to generalise. Many complete protocols can cost thousands of dollars, however, many animals will benefit from less than a complete protocol such that a ‘minimum cost’ may be hundreds, rather than thousands of dollars. Dose intensified treatment with autologous bone marrow transplant costs around $10 000 by the completion of treatment (proven beneficial for lymphoma patients).
  4. The service is not aiming to be a ‘chemotherapy clinic’ and referrals for owners wanting only an opinion are sought. Perth Veterinary Oncology sees referral oncology cases only, such that any patient sent for a second opinion will be advised to return to their primary care practice for management of other conditions, vaccination and worming.
  5. Multispecialist services: Referral to PVO also allows a patient to receive surgical, medical, radiological and dermatological opinions whilst staying with us. Alternatively, we can work with your practice or specialists elsewhere if required.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist. Owners of pets requiring referral should speak to their usual veterinarians to organise this.

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Melanomas of the skin are generally benign in behaviour in both dogs and cats. In dogs, 15% of skin melanomas, 33% of nail bed melanomas and 85% of poodle melanomas behave in a malignant manner. Melanomas of the skin are best removed surgically. Rapid growth, high mitotic rate (greater than 3 per 10 high power fields), or an ulcerated surface predicts aggressive behaviour and tumours showing these characteristics should be removed with larger margins and referred. Intralesional chemotherapy can be effective in locations for which surgery is likely to cause problems, such as the oral cavity or distal limbs.

Oral (non-lip) melanomas  behave in a malignant metastatic manner – grade is NOT predictive for outcome. Therapies include surgery or intralesional chemotherapy. Surgery must be aggressive with margins (i.e. hemimandibulectomy). Even with aggressive resection, the recurrence rate (local) is around 25%. Whilst median survival with surgery alone is around 8 months, at least a third of the dogs enjoy survival beyond 2 years. If surgery is not feasible or desired by the owner, intralesional therapy is successful in inducing remission in approximately 50% of patients. Median survival in responders is greater than 1 year.

Uveal melanomas in cats are generally malignant and require enucleation, whilst limbal melanomas are locally infiltrative and may be removed from the eye if diagnosed early.

Systemic chemotherapy is available for dogs with oral melanoma to control metastatic spread. Systemic chemotherapy is best reserved for melanomas with histopathologic or imaging evidence of aggressive behaviour. The presence of visible metastases does NOT confirm a grave short term prognosis. For those with reasonably good quality of life, therapy can be employed to maintain quality of life. Intralesional therapy can be employed if the primary mass is limiting quality of life and surgery is not possible or is refused by the pet’s owner.

Vaccine therapy is available for canine melanoma; Perth Veterinary Oncology is able to import the vaccine specifically for an individual patient. It has been proven to delay recurrence and slow progression in responders. It is administered by a needle-free device on 4 occasions at 2 week intervals, but otherwise is as readily and rapidly given as other vaccinations for dogs.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Haemangiosarcomas occur most often in German Shepherd dogs (and large breeds in general) and domestic short hair cats. Most tumours in both species occur in the spleen. However, it is important to note that in the dog, only around one half of splenic masses are haemangiosarcoma, and most of the remainder are benign. In many dogs with large spleens therefore, splenectomy is curative. However, canine splenic haemangiosarcoma has usually metastasised before recognition. The right atrium and brain are common sites, as well as the lungs. With splenectomy only, median survival times are reported as brief as 19 days following splenic rupture. Large samples from various regions of the tumour should be submitted for histopathology, as much of the gross appearance of splenic haemangiosarcoma is actually haematoma surrounding the tumour. In addition, unrelated benign liver masses are common in aged dogs, which may look like metastatic spread. It is therefore strongly advised to remove the spleen and biopsy lesions consistent with metastatic spread elsewhere , rather than euthanase based on gross appearance.

Cutaneous haemangiosarcomas occur most frequently in dogs with poor skin pigmentation. For dermal tumours, if the histopathology shows no invasion beyond the dermis with adequate margins, no further treatment is required. Although the evidence base is not as strong as for dogs, the high metastatic rate for both cutaneous and splenic forms of haemangiosarcomas in cats justifies consideration of adjuvant chemotherapy.

Therapy depends on the level of disease. Following surgery of the non-cutaneous forms chemotherapy is recommended. Many dogs are now living well into their second year, with occasional long-term survivors. Importantly, recent trial data shows that median survival times for dogs with metastatic disease are similar to those without – nodules on a chest radiograph do NOT indicate a lesser chance of responding to medication – those with more advanced disease will succumb more quickly however if they don’t respond to therapy. Staging should still be done to obtain a base-line. Measurement of cardiac troponin will identify 80% of dogs with cardiac involvement.  As an alternative treatment, anti-angiogenesis treatment such as metronomic chemotherapy can be employed. Anti-angiogenesis treatment does not tend to produce remission but prevents growth of the cancer in some patients. Patients suitable for this form of therapy must therefore have good quality of life when commencing treatment (as there is no point in prolonging the life of an ill patient). Ideal therapy employs both systemic chemotherapy concurrent with metronomic therapy as the disease free interval would appear to be additive.

What to do:

For cutaneous haemangiosarcoma, excisional biopsy is often enough. Refer if there are too many lesions to remove.

For non-cutaneous haemangiosarcoma, either refer once histopathology results are back, or for the initial surgery if preferred. Full staging (imaging) is readily done at Perth Veterinary Specialists. A biochemical panel is of no direct necessity, other than as a usual pre-surgical precaution. A CBC will be needed – anaemia is common due to haemorrhage, erythrophagia or haemolysis (not immune mediated). Bleeding defects are possible and should be checked pre-operatively.

When to refer:

At any point from documentation of the lesion, to as soon as possible following surgery. Histopathologic confirmation of the tumour is required before chemotherapy can commence. Dogs  with metastatic disease can still be treated, however with more short term risk.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Osteosarcoma has metastasised in over 95% of patients before diagnosis. Thoracic radiographs are positive at the time of diagnosis in only 10% of patients. The remainder have metastases too small to be visible. As tumours grow, their rate of division slows, and they become less sensitive to chemotherapy. Therefore, the ideal osteosarcoma patient for chemotherapy is one with the primary tumour removed and no visible metastases. Therapy is commenced once histopathology results confirm the disease (if no biopsy pre-amputation) or once recovery from surgery is adequate to leave the patient systemically well (often 1 week is appropriate). Treatment with surgery alone produces median survival times of around 3-4 months. Medical therapy allows most dogs a good year or two with around 20% going much longer. Osteosarcomas in regions other than the limbs are often still readily treatable with similar or better prognoses. For patients with early lesions in the distal radius, a limb-sparing procedure may be performed. This is a major surgical procedure with small but real problems of infection and local tumour recurrence, but is indicated when owners wish to preserve the limb at all costs.

Medical therapy alone is an option for patients unsuitable for amputation using chemotherapy combined with pamidronate (a drug which blocks bone invasion and increases susceptibility of the cancer to chemotherapy). Quality of life improves for 6 to 12 months in most cases.

Recent data shows that some dogs with advanced metastatic disease can still have prolonged survival following standard therapy. Median survival is around 2 months so clearly most dogs still succumb rapidly. Therefore, to euthanase on the basis of finding advanced disease will rob a small percentage of patients from extended survival. The decision therefore has to be made taking into account expected quality of life post-amputation and obviously an owner’s concerns. It is still humane to treat a dog with metastatic osteosarcoma in many cases given that amputation is often the most effective form of pain control, however short survival is expected.

What to do:

Biopsy is wise pre-operatively; however if the bone lesion is so severe that amputation will be required regardless of the diagnosis, and the owner consents, amputation with histopathology is acceptable. The differential diagnostic list includes other tumours (usually haemangiosarcoma or fibrosarcoma), fungal infection, bacterial infection, and bone cysts, probably in that order. Chest radiographs (both laterals and a DV or VD view) are worth taking and can be done at Perth Veterinary Specialists if you prefer (CT scan is of greater sensitivity). A biochemical panel is of no direct necessity, other than as a usual pre-surgical precaution. However, if done, a normal ALP activity is arguably a good prognostic sign.

When to refer:

At any point from radiographs showing a lytic & proliferative lesion in bone, to as soon as possible following amputation. Histopathologic confirmation of the tumour is required before chemotherapy can commence. Dogs  with metastatic disease can still be treated, however with less emphasis on long term control. Metastasis to other bone sites carries a better prognosis than to the lungs.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Carcinomas are cancers derived from epithelial cells. Common examples such as mammary carcinomas and squamous cell carcinomas have been covered on other pages. This page details the remaining carcinomas, such as anal sac carcinomas, bronchial carcinomas, and GI tract carcinomas. These tumours will often metastasise, typically to local lymph nodes and lungs, amongst other sites. They have a moderate response to chemotherapy. Hence, surgery is the first treatment. In addition:

  • Adjuvant chemotherapy reduces the microscopic burden remaining after surgery.
  • Neoadjuvant therapy reduces the size of the tumour to allow surgical removal.
  • Palliative chemotherapy improves quality of life and delays its progression.
  • Intracavitary infusion of chemotherapy can have excellent success in controlling effusion.
  • Intralesional injections of chemotherapy can be very effective when surgery is declined; they have the advantage of avoiding systemic side effects, yet increasing local response rates versus systemic chemotherapy.
  • Metronomic (frequent oral) chemotherapy can be employed to inhibit blood vessel development, slow growth and thereby maintain quality of life for an extended period. The new tyrosine kinase inhibiting drugs may have a place especially for anal sac carcinoma and thyroid carcinoma.


  1. Stage the disease. Ideally a combination of cytology of, for example, regional nodes and imaging – CT is preferable over radiographs.
  2. Remove visible tumour if possible, & then refer  to Perth Veterinary Oncology for advice re adjuvant therapy.
  3. If curative intent surgery is not possible, refer for advice on neoadjuvant vs palliative treatment.
  4. Costs vary greatly but are typically hundreds of dollars per chemotherapy treatment for most dogs and cats. Generally, from 1 to 6 treatments are given. Metronomic therapy costs a few dollars per day for most dogs.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Nasal, eyelids & ears:

Pre-cancerous lesions appear as erythemic, scaley regions. Once a non-healing ulcer is present, the lesion should be presumed cancerous. Carcinoma <2mm diameter may be non-invasive until random mutations allow angiogenesis. It therefore should be treated as soon as possible to prevent progression. Simple cryotherapy and strontium radiation are both suitable for lesions of this size. Once larger, inappropriate treatment will delay definitive therapy, worsening the prognosis. This is the main reason for failure in the treatment of this condition. Larger lesion treatments include surgical resection of the entire nasal plane, and spray application of liquid nitrogen onto the lesion. Intralesional chemotherapy is also successful for selected cases. Referral is encouraged for recurrent lesions, or ulcers 3mm in diameter or larger.


An SCC in this location may appear as a small proliferative mass or ulcer but is always aggressive. Radical surgery with tube feeding can provide most cats with a second year but is only suitable for committed owners. For small lesions surgery is palliative. If radical surgery is declined, intralesional chemotherapy can be performed. Most patients respond to treatment but do not enter remission; quality of life can be maintained for significant periods, however. Medical treatments (chemotherapy, intralesional chemotherapy) are supportive and may be very helpful with palliative expectations. Referral to Brisbane for hypofractionated radiation therapy appears to be successful based on early results.


Ventral abdomen

The entire non-pigmented ventral body is typically affected. Surgery is usually the first choice, but must be aggressive with margins of at least 1cm. Referral is wise to plan measures to slow or prevent other lesions from developing. When surgery is not appropriate, referral for deep cryotherapy, or intralesional chemotherapy is advised.


A pilot study has shown excellent success with chemotherapy and piroxicam, with many dogs not even requiring surgery. Durable responses occurred even in the face of regional node involvement. The tonsillar form of the disease carries a poorer prognosis. Compounds such as toceranib have anecdotal support.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Soft Tissue Sarcomas

Soft Tissue Sarcomas are a group of neoplasms including:


Synovial Cell Sarcoma


Granular Cell Myoblastoma


Nerve Sheath Tumour

Vaccine-induced Tumours




Malignant Mesenchymoma

They generally behave in a similar fashion. The important considerations are:

  1. A pseudocapsule of compressed cancer cells often surrounds them, which may make them falsely appear to be readily ‘shelled out’ during surgery. Wide margins are required, which may require a radical procedure such as amputation if done with curative intent.
  2. The metastatic rate is generally around 25% or less, and typically to distant sites such as the lungs. Tumours classed as high grade, or undifferentiated/anaplastic, have much higher rates of metastasis, typically in the 50%  range.
  3. Measurable (visible) disease is often best treated by surgery if at all possible.
  4. Patients with high grade joint tumours identified as ‘synovial cell sarcoma’ may be malignant histiocytosis and require different therapy. Referral is strongly advised.

The work up should start with an incisional biopsy. Note that an unsuccessful attempt at excision (i.e. removing without first determining that wide margins are required) will reduce the potential for definitive surgery to succeed. Thoracic radiographs (2 laterals, 1 DV view) are wise prior to definitive excision with very wide and deep margins. Referral for adjuvant chemotherapy is indicated for high grade or anaplastic tumours. If definitive surgery is declined or not possible, other options include:

  1. Metronomic chemotherapy following marginal excision (without resection of overlying skin if necessary). Treatment inhibits angiogenesis and thereby delays recurrence. In a recent trial, dogs treated in this manner had tumour recurrence on average after 3 years (rather than 6 months with surgery alone). Metronomic chemotherapy is daily and for life, at a cost of a few dollars per day.
  2. Electrochemotherapy. Generally one to two treatments only are required. Results are variable but can lead to reduction in tumour size and/or prolonged periods (1 year) of growth inhibition. No side effects other than local inflammation occur.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Vaginal Tumours

The majority of these tumours are benign, occurring in middle aged, entire bitches. Surgical removal with close margins should be curative. Occasionally, malignant neoplasms will occur and metastasis has been reported. The suitability for adjunctive treatment (chemotherapy, immunotherapy) is case specific in these patients. Transmissible venereal tumour is uncommon in urban regions. It is, however, highly responsive to chemotherapy with cure rates at around 90% with one month’s therapy. Surgery is unsuccessful and unnecessary in most cases. The diagnosis is readily made by cytology.

Ovarian Tumours:

These typically present in cats and dogs as abdominal distension due to the presence of a mass or ascites, and occasionally with signs of hyperoestrogenism (persistent oestrus, alopecia, and/or pancytopenia). It is safe to tap the abdominal fluid for cytological analysis, but do not attempt to needle the mass, as the cancer will readily seed the abdomen. Patients at high risk of metastasis, or with ascites will benefit from chemotherapy. Excisional surgery is required first for all cases. Abdominal ultrasound and thoracic radiographs (or CT) will help to better describe and stage the neoplasm.

Uterine Tumours:

In dogs, 90% of uterine tumours are benign, such that surgical removal is curative. In the cat, however, most are malignant. Vaginal discharge is the common presenting sign in both species. The use of chemotherapy in dogs and cats with malignant uterine tumours is probably best reserved for those with confirmed metastatic spread or high suspicion from histopathology results (such as vascular or lymphatic invasion, or a high mitotic rate).

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt  is Western Australia’s only veterinary oncologist.

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Canine Male Reproductive Tumours

The incidence is spread evenly between:

Sertoli Cell Tumours:

Commonly occur in older dogs with retained testicles. They are slow growing and may be oestrogenic. Up to half of dogs will show signs of oestrogen toxicity (anaemia, alopecia, prostatic non-neoplastic enlargement). The metastatic rate is approximately 15% or less. If metastases occur, regional lymph nodes are the most likely site. Abdominal organs and lung involvement have been reported but are less common.


This tumour type occurs in older dogs, most commonly in descended testicles. Metastases occur in up to 10% of dogs. They are rarely oestrogenic.

Interstitial Cell Tumours:

Common in the descended testicles of old dogs. They do not metastasise, but may be associated with testosterone production, perineal hernias and perianal adenomas.

Surgical removal of testicular tumours should be curative. If histopathology shows vascular or lymphatic invasion, or there is physical evidence of metastatic spread, then several chemotherapeutic regimes have proven effective in controlling disease. There have been no large controlled studies from which to accurately predict survival data, however.

Canine Prostatic Tumours

Almost all prostatic tumours in dogs are malignant, and most are carcinomas. Prostatic carcinomas in dogs do not appear to be influenced by androgens; in fact prostatic disease in an entire male is most likely non-neoplastic. Because castration prevents inflammatory prostatic disease, but not carcinoma, prostatic neoplasia is a likely explanation for prostatic enlargement in castrated males. The majority of these tumours will have spread by the time of diagnosis, most commonly to local organs such as the bladder, colon, and lumbar vertebrae, as well as iliac lymph nodes and lungs. The most common clinical signs include weight loss and hind limb gait change as well as neurologic damage or irritation affecting the urethra and colon.

Diagnosis can only be achieved by cytology or histopathology. Ultrasound examination is very helpful in documenting the disease and can be used to guide biopsies. Our preference however is a para-rectal Trucut approach, which is guided by palpation alone. Surgery typically results in urinary incontinence and is not expected to be curative. It is most useful for dogs that have urgent problems such as urinary obstruction for which correction will immediately improve quality of life. Chemotherapy can be very successful alone in relieving clinical signs, reducing the size of the tumour and providing a greater period of time for the dog. Cytotoxic treatment is combined with piroxicam. Without treatment most dogs are euthanased within weeks or a few months of diagnosis.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Mammary Tumours – Cats

Almost all mammary tumours in cats are malignant and metastatic. Hormone receptors are much less frequent; however there does appear to be a relationship with the administration of progestogens. Surgery is more aggressive than in dogs, as the disease is more locally invasive, such that unilateral mastectomy is advisable. Chemotherapy is advisable in cats with tumours larger than 3 cm diameter (median survival without treatment is 6 months) and/or with confirmed nodal spread. If visible tumour remains anywhere, responses are poorer.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Mammary Tumours – Dogs

The literature states that risk is clearly related to the hormonal status of the bitch, and determined by the first few heats. In reality it is uncertain – the strength of the studies to date has been variable, and therefore it is wise to consider that spaying MIGHT reduce the risk of mammary carcinoma in dogs. European studies have also shown that dogs that are lean at 12 months of age are at lower risk. Many tumours contain hormone receptors on their surface, suggesting that sterilising dogs with these tumours may slow their growth. The more aggressive the tumour is, the less likely it will have receptors. We therefore do not recommend desexing dogs with high grade mammary carcinomas if the intent is to slow the growth of the tumour. There may of course be other justifications relating to individual patients for desexing at the time of tumour removal.

In addition to lumpectomy, dogs should have a VD and left and right lateral thoracic radiographs taken. Regional nodes should be aspirated, or removed for histopathology if enlarged or connected to the tumour. Immunohistochemistry may help to grade the tumour more accurately. For the middle teats, consider ultrasound of the sublumbar nodes. Chemotherapy should be considered in those dogs with histopathologic confirmation of vascular invasion, tumours over 3cm in diameter, vimentin expression, OR nodal involvement. Without treatment, median survival time for these dogs is little more than 3-4 months. Alternatively, treatment using metronomic chemotherapy (at home, oral) to prevent blood vessel development in dogs with visible metastasis has the potential to delay tumour growth. Interestingly, 1 research group found marked benefit from the administration of DDAVP at the time of tumour removal, potentially through vascular disruption of micrometastatic foci.

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Mast Cell Tumours

In 1999, a study confirmed efficacy of vinblastine and prednisolone for the treatment of canine mast cell tumours. Numbers were too small however to make much of the statistics. From patients referred to Perth Veterinary Oncology for treatment, we have proven high success for dogs with grade II mast cell tumours and ‘dirty’ margins. Over 90% of dogs in this group have not had recurrence, followed for a minimum of 12 months. We published the first portion of these results in the Journal of the American Veterinary Medical Association (the first prospective canine mast cell tumour medical therapy paper).
Since then the grading schemes have improved allowing better prediction of those dogs at risk of death. All dogs classed as having a high Kiupel grade mast cell tumour should be considered candidates for adjuvant therapy.
In situations where appropriate margins (3cm in all directions) are not achievable or allowed, or even if surgery is not allowed at all, medical therapy is successful in many cases. A recent paper out of Colorado identified local inflammation or vomiting as being the most significant indicators of risk of death from mast cell tumours. Worst case scenario medical therapy (i.e. a highly aggressive metastatic mast cell tumour with no surgery performed) still achieves 22% disease free after 2 years, compared to median survivals of a few weeks without any therapy.

The use of intralesional water has been reported, but is unsuccessful at improving surgical success. It has been useful in shrinking tumours as an alternative to surgery, prior to chemotherapy. Its mode of action is purely osmotic. Electrochemotherapy has been proven as successful as surgery in recent trials for tumours of less than 3cm diameter.

Finally, Imatinib (Glivec), Masitinib (Masivet) and Toceranib (Palladia) have recently produced very encouraging results against bulky and microscopic disease in clinical trials achieving high remission rates with few serious adverse effects at the standard (though not necessarily the ‘recommended’) doses. Results appear to be temporary when used as monotherapy but allow patients without good surgical options to receive chemotherapy with greater likelihood of success. When combined with cytotoxics the potential for more durable results improves markedly.


Low Kiupel tumours with clear staging and good margins: monitoring only

Low Kiupel tumours with clear staging and incomplete margins: refer to Perth Veterinary Oncology for advice on electrochemotherapy

High Kiupel tumours or advanced disease: refer to Perth Veterinary Oncology for advice on medical therapy

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Lymphoma is the most common haematopoietic malignancy we see affecting dogs and cats. It is important to note that “lymphoma”, “lymphosarcoma” and “malignant lymphoma” are all the same condition and do not imply any difference in behaviour. It has been shown in humans with non-Hodgkin’s lymphoma that the lymphocyte becomes cancerous due to an accidental insertion of a proto-oncogene within the antibody-reading template during the response to an antigen. Research from our own genomic profiling has shown that the majority of dogs have deregulation in the mechanism that controls which genes are expressed. In short, this leads to silencing of anti-cancer genes, and an increase in the chance for mutations to occur. Further investigation into the genes involved is currently underway.

The most prominent recent change is the development of specific protocols for specific subtypes of lymphoma. In dogs for whom best-treatment is to be pursued, there are now 6 different protocols (CHOP, CHOP-Cyt, LOPP, LOPP-Cyt, CCNU, ChlorP). The choice hinges on grade, stage and subtype. Therefore a patient now requires full staging and immunohistochemistry to determine best treatment. Often these procedures are best done after referral as if pet owners do NOT want to pursue best treatment these procedures are of less importance and in many patients may be avoided with minimal impact.

The success rate treating lymphoma is generally high. Around 85% of dogs enter remission on most protocols. Non-multicentric forms in dogs can still respond, but as a group do not perform as well with respect to remission rates. Duration hinges heavily on grade, stage, subtype and choice of therapy. In cats, any form of lymphoma can respond well; around 2 in 3 cats enter remission whilst 1 in 3 are long-term survivors and often cured. Delaying treatment of high grade lymphoma, with or without prednisolone, worsens the prognosis.

Therapies range from 3 to 6 months of treatment, depending on the protocol. Costs can be high; the least expensive therapies typically cost around $200 per month, whilst the most intensive approaches can cost $10 000. Visits range from weekly (initially) for the intensive therapies, to monthly for the less aggressive protocols. The intention is that quality of life is normal during treatment as well as after, and this is realised for almost all patients.

Patients are readily referred to Perth Veterinary Oncology by on-line form, email, or phoning 9204 0400. Dr Ken Wyatt is Western Australia’s only veterinary oncologist.

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Canine oral melanoma

Melanomas are relatively common tumours in dogs, but rare in cats. In both species they can range in behaviour from benign (harmless) to malignant (potentially fatal). For many animals with a melanoma of the skin, surgical removal is curative. The most accurate way to predict the behaviour of a skin tumour is to have a sample sent to the laboratory. Melanomas in locations other than the skin, such as inside the mouth in dogs, or in the eyes of cats are generally more aggressive than the skin form. There are many ways we treat patients with melanoma:

  1. Surgery. This is the best first-line therapy, and is usually successful in preventing the tumour growing back at the same site. Unfortunately, there are no tests available that detect the tumour elsewhere until the disease is very advanced. In general, if the tumour appears malignant at the laboratory or occurs in a dog’s mouth or cat’s eye, it usually has already spread elsewhere in the body, and most often to the lungs, even though it may not be visible on x-rays for some time.
  2. Intralesional chemotherapy. Injecting chemotherapy drugs into the tumour reduces the tumour to the micropscopic level at its original site in about half of all cases. The doses used are too small to cause any side effects, and generally only require sedation and local anaesthetic. Most commonly, 4 treatments are given, each a week apart. Not all patients are suitable for this treatment.
  3. Systemic chemotherapy. This form of chemotherapy is used to treat the whole body and hence fight cancer wherever it has spread to. The way in which this is done in animals results in no serious side effects in 95% of patients. It is only used in patients who are at very high risk of their cancer having spread through the body.
  4. Anti-blood vessel treatment. In patients with very advanced disease but good quality of life, treatment against the blood vessels is more effective than fighting the cancer itself. Successful treatment limits further growth of the tumour.
  5. Vaccination. A vaccine is available that trains the immune system against the cancer and has been proven to maintain quality of life for much longer in dogs with advanced disease. The vaccine is given through the skin but without the use of a needle. It is administered on an out-patient basis, on four occasions each 2 weeks apart. Each visit is similar to those for the preventive vaccinations many dogs recieve annually.
  6. Nutritional changes and pain control. There are several changes that can be tailored to individual patient’s diets to improve quality of life. Pain control can be helpful in animals with advanced disease even if they do not show signs of pain.

Your veterinarian will advise you on how best to commence diagnosing and treating your pet’s cancer. At some point, a specialist opinion may be helpful to offer advice, or to commence some of the therapies listed above. Your veterinarian can organise referral to Perth Veterinary Oncology, at Perth Veterinary Specialists. At the time of consultation, you will be given as much information as possible on how effective any treatments are likely to be for your particular pet, how much cost will likely be involved, and whether any reactions to the particular treatments are expected.

In addition, we are able to advise on nutritional and other aspects designed to help your pet fight and/or tolerate the cancer better.

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Haemangiosarcoma is a cancer that forms from blood vessels. It most commonly forms in the skin, or internal organs such as the spleen or heart. In both dogs and cats, the internal form is very serious and without treatment, most patients have a life span of weeks to months. The skin form can be aggressive in some cases, and the laboratory results following surgical removal or biopsy will determine this. There are 3 successful forms of treatment available at present to fight this disease. The first is surgery. If possible, all visible disease needs to be removed. If this involves removal of a benign (or unable to spread) skin haemangiosarcoma, then surgery alone can be curative. For all other forms in dogs and cats, tumour spread elsewhere is expected to have occurred even though it usually will not be visible or detectable immediately.

The other 2 forms of treatment involve the use of medications. Medical treatment is available that results in significantly longer periods of normal quality of life following surgery. Whilst not every patient responds, most experience a good 6 to 12 months or longer. The treatment is given in such a way that side effects are uncommon. Treatments are generally given on 12 occasions, one and a half weeks apart and require that your pet be in hospital with us for as little as four hours on each occasion. Costs can be high, with medical cancer therapy treatments costing hundreds of dollars per treatment visit. Treatment is not curative though some patients will live normal lives for several years.

Alternatively, there is treatment available that can prevent blood vessel growth leading to a slowing down of tumour growth overall. Treatments aimed at preventing blood vessel growth are given at home, and require visits and blood testing a month apart initially, but less often later. Treatment costs are likely to be a few dollars per day for this form of therapy.

The 2 forms of medical treatment above work in different ways and therefore ideally are used together, giving many pets the potential for normal quality of life for much longer periods to spend with their family.

In addition, we are able to advise on nutritional and other aspects designed to help your pet fight and/or tolerate the cancer better.

Referral is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Osteosarcoma is the most common bone cancer in dogs. It most often occurs in a front leg away from the elbow, or a back leg close to a joint. It can also occur in bones of the spine or the skull. Because this is a serious disease that is rapidly fatal without correct treatment, your veterinarian will want to get a certain diagnosis very quickly. This can be done by taking a biopsy, and having a laboratory examine the sample. In some cases, the lesion is so aggressive that limb amputation may be the logical and humane first step – the sample is then taken at the time of surgery and submitted. Although the surgery required to remove an osteosarcoma is aggressive, it is important to realise that for many dogs this is the most effective form of pain control for the condition. Most dogs do very well after surgery, and are typically more comfortable within a few days of surgery than they were before. Dogs generally will not show symptoms of chronic pain – by the time it is severe enough to notice, for example by decreased appetite, the dog has suffered enormous discomfort.

Chest x-rays are often taken prior to surgery. If the tumour can be seen in the chest (about a 10% chance), most dogs will not live more than 2 or 3 months even with treatment. If there is no tumour visible in the chest, this means that the cancer is not advanced (but will almost certainly be hiding there) and that cancer treatment is likely to be worthwhile. Unfortunately, if surgery is the only treatment, most dogs will not live more than 4 months. With cancer therapy, about half of dogs will still be doing well 12-18 months after surgery, and about 1 in 5 will have many years of good life. Cancer therapy therefore obtains good control of the disease and importantly in most dogs causes no side effects. Only one dog in 20 will have a serious reaction to the medication, which is most often rapidly controlled.

Because of the nature of the drugs used to treat osteosarcoma, you will need to be referred to Perth Veterinary Oncology. In many cases, your veterinarian will be the best person to do the initial surgery. Alternatively, there are surgical specialists at Perth Veterinary Specialists for whom your veterinarian can arrange referral.

Thanks to new medications, dogs with biopsy-proven osteosarcoma can now have effective treatment WITHOUT needing surgery. Medical-only treatment is not as reliable or as durable as standard treatment (surgery plus medication) and therefore should only be used in circumstances where the patient is not expected to cope with amputation (due to severe arthritis in other limbs, for example).

Costs can be very high with these sorts of treatment. Surgery may cost several thousand dollars, and medical cancer treatments can cost the same again. The cancer therapy is given via a drip, every 2 to 3 weeks on up to 6 occasions, and does not require overnight hospitalisation. It is important to remember that all the treatment for this disease is designed to restore quality of life, and to then provide as much time as possible. Achieving good quality of life is the primary objective.

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Other Carcinomas

Carcinomas are cancers that originate in tissues that line the inside or outside of organs, such as the skin, lungs and intestine, or from glandular tissues such as the breast. They vary in how aggressive they behave; for some, surgical removal is curative, whilst for others metastatic spread through the body occurs long before the first ‘lump’ is detectable. In order to estimate the behaviour of a cancer, we use information from your description of its appearance and growth, its location, and importantly, the tumour’s appearance under the microscope. This last step means that a biopsy is generally necessary to advise you fully, although there are selected situations where this can be avoided. The biopsy can be taken with a minimally invasive instrument, through to removing a large piece, or if cure is likely, the whole mass. Your veterinarian is well-trained to make the decision on how to biopsy and when to refer to a specialist. For some carcinomas, additional tests on the biopsy can help determine what risk your pet is at and a specialist can discuss these with you. They do not typically required additional samples to be collected.

Treatment generally is surgical and/or using medication. Medication can be anything from tablets at home, through to injections of chemotherapy which most often do not cause any side effects in cats and dogs. The aim of medical treatment can be to improve quality of life by reducing the amount of cancer present, through to preventing further growth of the cancer, or alternatively palliative treatments are often available that focus on the symptoms rather than the cancer. The decision regarding which of these therapies best suits your pet is generally best made after compiling all the information available, following referral to a veterinary oncologist. Remember that the aim of treating any cancer in pets is based on achieving and maintaining quality of life ahead of all else.

Costs vary depending on what treatment is used. Whilst extensive surgery or chemotherapy can easily cost thousands of dollars, treatments are often available that cost considerably less.

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Squamous Cell Carcinoma

Squamous cell carcinoma is a common cancer of the skin and mouth in dogs and cats. The skin form is typically the result, as in people, of excessive sun exposure, but not necessarily sunburn. Skin cancer is often best frozen or surgically removed, and your local veterinarian is often the best person to do this, without the need for referral to a specialist. However, in some situations your pet will benefit from the expertise available at Perth Veterinary Oncology.

When the cancer occurs in the mouth, it is not the result of sunlight exposure – the cause is unknown, though for cats it has been associated with household smoke. In cats, the disease is particularly aggressive and generally not curable. Surgery can be done, but must be aggressive. Alternatively, injections of chemotherapy can often control the disease, and do not cause ‘chemotherapy’ side effects. For dogs, the prognosis can be better, and for some, cure is a likely outcome.

Your veterinarian will advise you on how best to commence diagnosing and treating your pet’s tumour. At some point, a specialist opinion may be helpful to offer advice, or to commence some of the therapies listed above; your veterinarian will be happy to organise referral. At the time of consultation, you will be given as much information as possible on how effective any treatments are likely to be for your particular pet, how much cost will likely be involved, and whether any reactions to the particular treatments are possible. The only animal cancer specialist in Western Australia is Dr Ken Wyatt at Perth Veterinary Specialists.

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Soft tissue sarcomas are a group of tumours that grow from connective tissues in the body. Often they don’t spread elsewhere but can be a problem due to invading very deeply. High-grade tumours can spread through the body, and the risk of this happening is best determined by submitting a piece of the tumour to the laboratory.

If the risk is low, there are 5 types of treatment available for your pet:

  1. The most effective treatment is surgery, however this must be aggressive to have any chance of cure. In many cases this may mean removal of nearby structures, and for limb tumours, amputation may be required.
  2. Less aggressive surgery not intending to cure can be followed by daily at-home medication. Recurrence will occur but hopefully after several years; this treatment therefore may be most useful for older pets.
  3. Injections of chemotherapy into the tumour. The advantage of this technique is that very high concentrations of drug are placed into the tumour, however very little diffuses out into the patient. Chemotherapy side effects therefore do not occur.
  4. Metronomic therapy. Frequent (daily to every second day), at home treatment which inhibits new blood supply to the tumour and therefore inhibits growth. This approach has proven very successful for low to moderate grade soft tissue sarcomas in dogs, with excellent results.
  5. Radiation therapy following surgery. This can be effective though currently requires travel to Brisbane.

If the tumour is classed as high grade, the potential for spread becomes very high. In this instance it is preferable to follow removal of the tumour with medical treatment aimed at removing remaining cancer cells elsewhere in the body. This should result in your pet having a significantly longer period of normal quality life. These medications generally will not make your pet ill.

In most cases surgery will be done by your veterinarian, however there will be some procedures for which they may prefer that your pet is referred to a specialist.

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Ovary Uterus Vagina

Ovarian Tumours:

These are uncommon in dogs and cats. Most of the tumours that occur in both species are cancerous and have spread by the time of diagnosis to other parts of the abdomen, as well as the lungs. Most of the time, the first symptom will be an enlarging abdomen. Sometimes, the tumours produce the female hormone oestrogen, which leads to enlargement of the vulva, persistent signs of being on heat, hair loss, or pale gums. If your veterinarian suspects the presence of an ovarian tumour, surgery will be necessary to be certain, and also to remove the tumour. Ultrasound examination may help beforehand to obtain more information about the mass. Surgery can be curative, and is therefore strongly advised. However, for many pets, evidence obtained by ultrasound, at surgery, or from the laboratory report following examination of the tumour, indicates that the tumour has spread elsewhere in the body. In this instance, medication can be very successful in markedly delaying recurrence of the disease. Your veterinarian will advise referral to Perth Veterinary Oncology in this instance.

Uterine Tumours:

Fortunately for most dogs with this rare tumour, the problem is benign and cured by surgery. For cats however, the tumours are typically advanced at diagnosis, and have spread. The most common symptom in both species is a discharge of vaginal fluid. Surgery is required in all cases. For some, medication will be required afterwards, given by Perth Veterinary Oncology so that quality of life can be maintained for a longer period.

Vaginal Tumours:

These tumours can grow to be very large, but fortunately are mostly benign. Surgery therefore is typically successful in curing the patient. Occasionally, cancerous tumours will appear in this location. Your veterinarian may suggest referral in this instance.

Your veterinarian will advise you on how best to commence diagnosing and treating your pet’s tumour. At some point, a specialist opinion may be helpful to offer advice, or to commence some of the therapies listed above. Your veterinarian can organise referral for you. Costs can range from hundreds to thousands of dollars for some treatments. At the time of consultation, you will be given as much information as possible on how effective any treatments are likely to be for your pet, how much cost will likely be involved, and whether any reactions to the particular treatments are possible.

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Drs Ken Wyatt and Amy Lane are the only Veterinary Oncologists in Western Australia.

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Testicular cancer

Fortunately, testicular cancer in dogs is usually much less aggressive than in man. For the majority of dogs, surgical removal of the tumour is curative. Whilst many people are uncomfortable with the idea of castrating a pet, we all have a duty to safeguard our pet’s health, and castration is kinder than cancer. In general, this surgery will not change your dog’s behaviour other than reducing dominance aggression (but not territorial or protective aggression). Castrated dogs only put on weight if overfed. In most instances, referral is not required; your own veterinarian is typically the best person to perform this procedure.

In some instances, these tumours can spread elsewhere. Evidence of lymph node enlargement or the results from the laboratory that examine the tumour after surgery may suggest that more than surgery is necessary. In this case, your veterinarian will advise referral to Perth Veterinary Oncology to discuss treatment of the cancer. Medication can do a lot to keep your dog comfortable and generally doesn’t cause any illness itself.

Finally, some testicular cancers can produce the female hormone, oestrogen. This produces skin changes and hair loss, but can also cause serious damage to the bone marrow that may be irreversible. A blood test will detect the marrow injury rapidly.

Prostate cancer

Prostate cancer is the most common reason for a castrated dog to have a large prostate. Castration does not prevent prostate cancer in dogs, and does not slow it down once it has developed. Prostate cancer in dogs can respond very well to cancer drugs. The result is not cure, but often a dog with normal quality of life for another year or two. Surgery can sometimes help but will cause urinary incontinence; its main use is to restore the ability to urinate. There are several ways that many of the symptoms of prostate cancer in dogs can be eased with various medications.

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Mammary (breast)

Breast cancer, usually mammary carcinoma, is a relatively common disease in dogs and cats. Animals desexed at or before 6 months of age have been reported to have the lowest risks in some studies but this is by no means certain. Around 5 out of every 6 breast growths in cats and half in dogs, are malignant. This means that they are showing changes under the microscope which indicate the potential for the cancer to spread elsewhere in the body, and therefore to be fatal. Because these changes are only visible in relatively large sections of tissue removed from the lump, the first step that must be taken is removal of the lump itself. If the laboratory that analyses the tissue reports that the mass is a malignant cancer, then several things can be done. Firstly, sometimes more aggressive surgery may be necessary. Secondly, it is worth taking some x-rays of the lungs to see if the cancer is advanced. Note that if the x-rays do not show the tumour, it only means that the cancer is not advanced. (It takes over 100 million cancer cells to show up on an x-ray.) In some cases, further tests can be done on the surgery sample to more accurately determine how aggressive the tumour is; these can readily be organised on referral to a specialist and can be run on the original surgical sample. If the report from the laboratory shows specific changes that mean the tumour has very likely spread (or metastasised) then medical treatment is indicated. Most dogs and cats with cancers in this category do not live more than 3-6 months without further help. Medical treatment has been shown to have the potential to dramatically reduce the numbers of cancer cells elsewhere in the body, meaning that the patients retain normal quality of life for significantly longer periods of time. The majority of patients do not have any side effects limiting their quality of life whilst they are receiving treatment. Treatment is not necessary for every patient, and can be costly. By the completion of treatment (usually 1-3 months), most treatment protocols will have cost thousands, not hundreds of dollars. Whilst this type of treatment may not be for everybody, at Perth Veterinary Oncology we can also advise on other aspects of cancer including nutritional intervention and pain assessment and control. Simple treatments are also available to help slow the cancer’s growth.

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Mast cell tumours

Mast cell tumours are the most common cancers of the skin and underlying (subcutaneous) tissue in dogs, but do not occur in people. Whilst the genetic abnormalities that occur within the cancer are well characterised, the causes are unknown. Breeds such as Boxers, Labrador retrievers and Staffordshire bull terriers are at much higher risk than other dogs. Almost all of these cancers begin in or under the skin, but rarely can originate in the stomach or intestine. The tumours themselves generally appear as a lump in the skin, and may appear reddened or ulcerated. The tumours vary greatly in their degree of malignancy; some will never be more than a small lump whilst others will grow rapidly and spread elsewhere in the body.

Initially, a diagnosis must be made. At some point, a sample of tissue will need to be sent to the laboratory to determine how aggressive the tumour is. Generally, the cancer will be given a grade, which is an estimate of how aggressive the cells appear to be. There are 3 different ways of assessing grade for this tumour. The most frequently used are the 2 most recent. The first, where grade I tumours are low grade and generally harmless, and grade III tumours are high grade and spread rapidly is helpful except that the middle grade, 2, is almost meaningless at estimating prognosis. The newest system, by Dr Kiupel, places the tumours simply as high (aggressive) or low and appears accurate at determing the risk of the tumour causing death.

All mast cell tumours tend to burrow deeply into the surrounding tissue such that the visible mass is no more than the ‘tip of the iceberg’. The surgeon therefore will take as much tissue as possible around the cancer to decrease the odds of leaving any microscopic cancer behind. Often, only surgery will be necessary to effect a cure. As an alternative to surgery, injections into the tumour are available that are equally effective for smaller mast cell tumours (less than 3cm diameter).

For high grade tumours or especially if the location prevents aggressive surgery from being performed (e.g. the leg or face), medications are available that can make a dramatic difference to the future of these dogs. Furthermore, 95% of the time, there are no side effects. Serious side effects occur 1% of the time. The majority of dogs with mast cell tumours can be cured.

The medical treatment itself is usually intravenous injections or oral capsules, which are quick and largely painless. Most dogs will receive 8 or 10 treatments over 12 to 16 weeks. Costs can be significant, with each treatment visit being hundreds of dollars.

The most significant break through in recent time has been the introduction of the drugs Imatinib, masitinib and toceranib, which can produce remarkable (though temporary when used alone) control for patients with advanced disease. Their short term use allows many dogs to initiate standard therapy and maintain their quality of life for much longer periods of time. Used continuously, toceranib has been proven to increase the likelihood that dogs with high grade tumours are still around into the long term (i.e. years not months).

Referral to Perth Veterinary Oncology is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Lymphoma is the most common cancer formed from blood cells that occurs in dogs and cats. However, the chance of any one dog developing this disease over any one-year period is less than 1 in 1000. This disease is similar to non-Hodgkin’s lymphoma in people, and has been called lymphosarcoma and malignant lymphoma. The different names don’t indicate any difference in the condition. Lymphocytes are the type of white blood cells that produce antibodies (B cells) and help to fight against viruses and cancers (T cells). Most lymphomas are due to cancerous B cells. Because the natural behaviour of lymphocytes is to circulate around the body, the same behaviour continues once they become cancerous. They are typically systemic, or body-wide, regardless of where the disease is detectable. For most, the cause of the disease is unknown, although there may be a connection in dogs to heavy exposure to paints and solvents, high voltage power lines and 2,4 D herbicide. In cats, sharing a house with smokers can increase the risk as does FIV (the feline “AIDS” virus) and Feline Leukaemia Virus. Dog breeds such as the boxer and golden retriever appear to be at increased risk. There has been a line of bullmastiffs reported with an extremely high risk of lymphoma. The exact reasons for these predispositions are unknown.

The disease is rapidly fatal for most. Most dogs and cats succumb within 2 months of diagnosis if treatment is not initiated promptly. This is an average figure – some will have less aggressive forms and live for 6 or 7 months, whilst some will decline within days. Tests run on a biopsy of the tumour can accurately determine the sub-type of lymphoma, and whether the disease is likely to behave in an aggressive manner or not. These tests also determine what types of medication are likely to be most effective. At Perth Veterinary Oncology, the biopsies for these tests are usually done by taking core samples rather than a surgical approach. This minimally invasive test allows for rapid recovery and minimal discomfort.

Most dogs develop the high-grade (aggressive and rapid) form. Treatment can be either palliative or can aim to reduce the cancer burden directly. Palliative therapy often includes corticosteroid (“cortisone”) tablets, which can produce a dramatic short-term benefit in about half of all patients. Length of life is not improved, but quality of life is often much better. The only therapy proven to be very effective in pets is medical therapy. Drugs are used to kill large numbers of cancer cells (well over 99%), which places the patient into remission. Remission means that the tumour cannot be detected, and is unable to cause any symptoms. Hence your pet will have normal quality of life. For the majority of patients there exists a therapeutic “window” such that medication can result in complete remission for good periods of time, with ZERO side effects. With all treatments, there exists a risk, and around 1 in 20 patients will have serious reactions to the medication.

Referral is easily organised through your usual veterinarian. Dr Ken Wyatt is the only Veterinary Oncologist in Western Australia.

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Our Team


Ken graduated from Murdoch University in 1990 and after a few years in Perth general practice gained Membership to the Australian and New Zealand College of Veterinary Scientists by examination in 1995. Following a residency at Murdoch, with an externship at Massey University in New Zealand and further experience in the US, Ken successfully gained Fellowship to the College in 2000. (It is this qualification that allows application for the recognition of specialist status. There are currently 10 veterinary oncologists in Australia, but none in WA other than at Perth Veterinary Oncology). Ken is currently the President of the Oncology Chapter of the Australian and New Zealand College of Veterinary Scientists.

He has a dog Max and 2 cats, Charlie and Stanley. Max was an unwanted farmer’s puppy who proves why active dogs and lawn aren’t found in the same yard. Luckily Max is more respectful of the couch. Charlie and Stanley wasted no time letting Max know to do exactly as they command.


Finlay J, Wyatt K, Novel use of immunohistochemistry for phenotypic evaluation of circulating neoplastic lymphocyte populations. New Zealand Veterinary Journal, 2015 in press

Setyo L, Wyatt K, et al.  Furosemide for prevention of cyclophosphamide-associated hemorrhagic sterile cystitis in dogs receiving metronomic low-dose oral cyclophosphamide, VCO, 2016, in press

Finlay J, Wyatt K,          Recovery from cyclophosphamide overdose in a dog, JAAHA, 2015 in press

Finlay J, K Wyatt, Evaluation of the risks of chemotherapy in dogs with thrombocytopenia, VCO, 2015 in press

Lane AE, Wyatt KM. Paraneoplastic hypercalcemia in a dog with thyroid carcinoma. Can Vet J. 2012 Oct;53(10):1101-4.

Lane AE, Chan MJ, Wyatt KM.Use of recombinant human granulocyte colony-stimulating factor prior to autologous bone marrow transplantation in dogs with lymphoma. Am J Vet Res. 2012 Jun;73(6):894-9.

Lane A, Black M, Wyatt K.Toxicity and efficacy of a novel doxorubicin and carboplatin chemotherapy protocol for the treatment of canine appendicular osteosarcoma following limb amputation. Aust Vet J. 2012 Mar;90(3):69-74.

Davies D, Wyatt KM et al (2004) Mast cell tumour chemotherapy, J Am Anim Hosp Assoc. 2004 Mar-Apr;40(2):124-30

Wyatt KM & Wyatt GL (2002) Evaluation of a manual technique for detection of neutropenia and thrombocytopenia in dogs receiving chemotherapy, June 15 J Am Vet Med Assoc

Wyatt KM & Robertson ID (1998) Canine lymphosarcoma – a West Australian Perspective, Aust Vet Practit, 28(2): 63-66.

Wyatt KM & Labuc RH (1998) CK-MB in canine cardiac disease, Aust Vet J, 76(12):826.


Wyatt KM (1998) Perianal fistula – an immune mediated disease, Aust Vet Practit, 28:152-3

Wyatt KM (1998) Obstetrics and the veterinary nurse, Aust Vet Nurse J, 14:12

Wyatt KM (1999) Oncology: An introduction, Aust Vet Nurse J, 22:5-9

Wyatt KM (1999) Diabetes mellitus and the veterinary nurse, Aust Vet Nurse J, 20:7-9


O’Hara M, Wyatt KM et al, 2001, Laryngeal rhabdyomyoma in a dog, Aust Vet J, 79;817-821

Jaensche S, Wyatt KM et al, 2002, Skin tumours in a goose, Aust Vet J, 80; 277-280

Marchevsky AM, Yovich JC, Wyatt KM, (2000), Pancreatic pseudocyst causing extrahepatic biliary obstruction in a dog, Aust Vet J, 78(2): 99-101

Wyatt KM (1999) An enterovesical foreign body in a dog, Aust Vet J, 77(1):27-9

Wyatt KM, (1998) Peritoneal Dialysis in a dog with acute ischaemic renal failure, Aust Vet Practit, Aust Vet Practit, 28(4): 146-151

Wyatt KM, (1998) Acquired myasthenia gravis in a Jack Russell terrier, Aust Vet Practit, 28(3): 111-115


The Veterinarian, “How To Treat”- Feline SCC, November 2002

VAB, Update on medical oncology, 2002

The Veterinarian, “How To Treat”  – Chemotherapy Toxicity, May 2001

The Veterinarian,

– Digoxin Toxicity, May 1996

– Insulin-Secreting Tumours, June 1997

– Lymphosarcoma, June 1998

– Haemangiosarcoma, January 2000

– Chronic Nasal Discharge, March 2000

– Mast Cell Tumour, April 2000

– Osteosarcoma, September 2000

– Mammary carcinoma, April 2002


Wyatt KM (2012) Stem Cells in Cancer, ANZCVS Science Week

Wyatt KM (2012) Veterinary Oncology Update, AVA Annual Conference

Wyatt KM (2005) Pathophysiology of Multiple Myeloma, ACVSc Science Week

Wyatt KM (2004) Adjuvant Chemotherapy for High-grade Mast Cell tumours, ACVSc Science Week

Wyatt KM (2004) Electrochemotherapy, ACVSc Science Week

Davies D, Wyatt KM, et al (2002)Vinblastine & prednisolone in the therapy of canine mast cell tumours, ACVIM

Wyatt KM (2001), Methylation deregulation in canine lymphoma, Veterinary Cancer Society annual meeting, Baton Rouge, Louisiana, USA.

Wyatt KM (1999), The utility of manual blood counts in predicting automated cell counts, ACVSc Science Week, Sydney

Wyatt KM (1999), The use of azathioprine and prednisolone in the treatment of perianal fistulae, BSAVA, Birmingham (presented by Dr Robert Labuc)

Wyatt KM (1998), Immunosuppressive therapy for perianal fistulae, ACVSc Science Week, Sydney

Wyatt KM (1998), An enterovesical foreign body – a case report, ACVSc Science Week, Sydney

Wyatt KM (1997), Novel Corticosteroids for Inflammatory Bowel Disease, FAVA congress, Cairns

Wyatt KM (1997), SCC of the nasal plane in cats, FAVA congress, Cairns

Wyatt KM (1997), SCC of the nasal plane in cats, AVA conference, Brisbane

Dr Jessica Finlay|Oncologist, BVSc (Hons) FANZCVS

Jessica graduated from Melbourne University in 2004 with first class honours, moving to a general practice in Victoria, and then Tasmania. From there, she undertook post graduate studies in Oncology as well as successfully gaining Membership to the Australian and New Zealand College of Veterinary Scientists in Small Animal Internal Medicine (including Oncology) by examination. She also took on a Masters Degree over this time. She completed her residency (specialist training) in medical oncology in January 2015 with us and brings the combination of enthusiasm and a tireless thirst for knowledge. In 2013 she presented an abstract at the national meeting of the Oncology Chapter of the ANZCVS, attended the Veterinary Cancer Society annual conference in Minnesota and also completed her externship at Colorado State University.


Finlay J, Wyatt K, Novel use of immunohistochemistry for phenotypic evaluation of circulating neoplastic lymphocyte populations. New Zealand Veterinary Journal, 2015 in press


Finlay J, Wyatt K,          Recovery from cyclophosphamide overdose in a dog, JAAHA, 2015 in press

Finlay J, K Wyatt, Evaluation of the risks of chemotherapy in dogs with thrombocytopenia, VCO, 2015 in press

Rotating Veterinarian in Oncology|

Each year, 3 veterinarians are chosen to work with us for 4 months in each of the disciplines of Oncology, Internal Medicine, and Emergency