Osteosarcoma (Bone Cancer)
Osteosarcoma is a malignant cancer of the bone. This form of cancer starts inside the bone and works its way to the surface in a relatively short period of time. The body’s reaction to the destructive (lytic) activity of this tumor is to compensate by laying down new bone on the outside surface (cortex) of the bone. Eventually the cancer eats through the cortex, where the strength of the bone is, resulting in a pathological fracture. Unfortunately this type of cancer is very painful for the pet.
The first symptom the owner may be aware of is when their pet begins to limp. Often this may be confused with a soft tissue injury such as a sprain or a strain. As time goes by the limp gets worse rather than better. Your veterinarian may suggest a x-ray be taken to investigate the cause of the limp. In some cases there may be a swelling to the bone. In the early stages of this disease bone cancer can be confused with a bone infection called osteomyelitis or with a bone cyst that is benign in nature. While the appearance of osteosarcoma will become pathopneumonic after a period of time alternatively the diagnosis can be confirmed with a biopsy of the tissue.
If treatment is elected rather than euthanasia as the alternative then the most common treatment is amputation, complete or partial, of the affected limb. Unfortunately, this type of tumor has a reputation for spreading, via the blood stream, to the lungs and in some cases to the regional lymph nodes. Chemotherapy is the recommended treatment to kill the cells that have spread. Even under the best of circumstances, with aggressive treatment, the prognosis remains poor for the long-term survival from this disease.
Considerable interest exists for this disease due to its similarity in man. There are constantly new treatment investigations being conducted at universities and research institutions. Efforts like these have often extended the quality of life as well as the longevity of the cancer patient. Chemotherapy side effects in animals are not as horrible as they are for man due to the different dosage schedules that are followed. The philosophy of chemotherapy in animals is to extend the quality of life compared to killing all of the cancer cells in man regardless of the side effects. As every day of life is considered precious, treatments for cancer are more common today then they were in the past. Specialists, called oncologists, are now more common place for animals. Many veterinarians today are knowledgeable and capable of treating your pet with chemotherapy if the need should arise.