Bone Cancer (Osteosarcoma) in Cats

Cancer is defined as abnormal, uncontrolled cell growth. Bone cancers in general are rare in cats, but of the possible subtypes, osteosarcoma is the most common. Rear limbs are more frequently affected than front limbs.

Although not an emergency, any cat that is showing symptoms of OSA should be examined as soon as possible.

Symptoms tend to get worse as the disease progresses. Symptoms consistent with OSA can also arise due to spread of neoplasia from other areas of the body or other more common types of cancers like lymphoma, fibrosarcoma, and hemangiosarcoma .

If advanced, OSA can lead to pathological fractures. Pathological fractures occur with little trauma and are caused by loss of bone integrity due to the tumor.

Bone cancers in general are rare in cats. Unlike dogs, who seem to have a genetic predisposition to OSA, no genetic link is apparent in cats.

The underlying cause of OSA is unknown but previous trauma, bone infection, or exposure to radiation are thought to be possible contributing factors.

Other symptoms are dependant on tumor location.

A physical exam, detailed history, complete blood count, chemistry panel, and X-rays typically suggest OSA. A bone biopsy is needed to make a definitive diagnosis. Additional diagnostic imaging is used to identify cancer spreading to other areas of the body.

Surgical removal of the affected bone is typically the only form of treatment. A 2022 study suggests that adding chemotherapy to the treatment plan after surgery may increase survival time. Further studies to gather information on metastasis rate, prognosis, and other factors are needed before new recommendations on chemotherapy are made.

Adding radiation therapy may add some benefit when complete surgical resection is not possible.

Palliative care includes pain relief and anti-inflammatories when more aggressive therapy is not possible.

Follow up monitoring includes a complete physical exam and repeated X-rays every 3 months during the first year post surgery and then once every 4-6 months thereafter.

Long term prognosis is guarded and varies based on location of the tumor and treatment provided. Survival time following amputation alone is 24-44 months. Survival time for tumors in the axial skeleton (skull, vertebral column, and ribs) is only 6 months.

With no breed, sex, or genetic link, OSA cannot be prevented.

OSA is not contagious.

OSA is rare in cats.

• Amputation
• Radiation therapy
• Anti-inflammatories and pain relief
• Palliative care
• Euthanasia