Haemangiosarcomas occur most often in German Shepherd dogs (and large breeds in general). Most tumours in both dogs and cats 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, liver, lungs, and brain are common sites. With splenectomy only, median survival times are typically ~3 months. Large samples from various regions of the tumour should be submitted for histopathology, as much of the gross appearance of splenic haemangiosarcoma may be haematoma surrounding the tumour. In addition, unrelated benign liver masses are common in aged dogs, and may appear similar to 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.
Therapy depends on the stage of disease. Following surgery of the non-cutaneous forms, maximum tolerated doses of chemotherapy is recommended. Some dogs are now living well into their second year, with occasional long-term survivors. Staging should be preformed to obtain a base-line. As an alternative to MTD chemoterapy 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 MTD chemotherapy concurrent with metronomic therapy.
What to do:
For cutaneous haemangiosarcoma, excisional biopsy is often enough. Refer if the lesion is large or 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 and Dr Jessica Finlay are the only Veterinary Oncologists in Western Australia.