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. 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 treatment.

If the risk is low, there are 3 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 metronomic therapy. This is a relatively new approach which targets the blood supply to the tumour and may also make the tumor more visible to the immune system. Recurrence will occur but hopefully after several years; this treatment therefore may be most useful for older pets. Alternatively, radiation therapy can be used to ‘mop up’ cancer left behind following surgery.
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. Success rates are lower than with surgery.

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.

Chest x-rays are often taken prior to surgery. If the tumour can be seen in the chest (about a 10% chance), then treatment aims to restore quality of life for up to a year . 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 has a greater likelihood of achieving long term control. Unfortunately, if surgery is the only treatment, most dogs will not live more than 3 or 4 months. With cancer therapy, about half of dogs will live 16 months or more, and about 1 in 5 will be cured. Cancer therapy therefore obtains good control of the disease and importantly in most dogs causes no side effects: 70% of the time our treatments have no side effects at all, and another 25% produce only brief, mild problems. Only one dog in 20 will have a serious reaction to the medication, which is almost always successfully and rapidly controlled.

Because of the nature of the drugs used to treat osteosarcoma, you should be referred to a veterinary oncologist.

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). It employs a combination of chemotherapy and either a new bone drug called pamidronate or radiation.

Costs can be very high with these sorts of treatment. Surgery may cost up to 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. Quality of life is the primary objective.