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 diagnosis very quickly. This can be done by taking an aspirate or 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 or CT 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.
Where patients are not expected to cope with amputation (for example due to severe osteoarthritis in other limbs) radiation therapy followed by chemotherapy can have provide similar outcomes to those that undergo amputation and chemotherapy.
New medications, provide effective treatment WITHOUT needing surgery or radiation therapy. Medical-only treatment is not as reliable or as durable as standard treatment (surgery or radiation therapy plus chemotherapy).
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, but 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.