Secondhand Smoke Causes Cancer in Cats

Some cats are genetically more likely to develop lymphoma, but that risk grows if someone in the home is smoking.

Siamese, Oriental shorthairs, Javanese, and related breeds are predisposed to lymphoma. Stockorm/Shuttertstock

Q: Tao, our 11-year-old part-Siamese cat, was diagnosed with lymphoma. He has always been an active, healthy indoor cat, so I don’t understand how this could have happened. What causes lymphoma in cats?

A: I’m sorry to hear about Tao’s lymphoma, also called lymphosarcoma. It is the most common cancer in cats—and the incidence is higher in cats than in any other species.