Bone Cancer Metastases

The chance may be greater than previously thought

Cats with bone cancers tend to be lame and usually have swelling at the cancer site. The area is often painful and feels warm to the touch. Amputation is commonly recommended as the best therapeutic option, and concern for metastasis (spread of cancer to other parts of the body) has been historically low. This idea, however, has been challenged by a Japanese retrospective study investigating the outcomes of cats with bone cancer who had limb or scapula (shoulder-blade) amputations.

The study included 67 cats with osteosarcoma (70% to 80% of bone cancers in cats are osteosarcoma). The most common site for cancer was the femur, followed by the tibia or fibula, and then the scapula. Unfortunately, about 40% of the cats in the study experienced distant metastases of their cancer. Osteosarcoma of the humerus had a particularly high rate of metastasis, occurring in six of seven cases.

If your cat develops bone cancer and undergoes an amputation as treatment, you still need to follow up with regular screening for evidence of metastasis. In some cases, additional therapy (i.e., chemotherapy) may be recommended to treat any metastatic lesions that are identified.

JAVMA Jan15,2022 Vol 260 No S1 Outcome of appendicular or scapular osteosarcoma treated by limb amputation in cats: 67 cases