Lymphoma

Lymphoma is a cancer of the immune system's lymphocytes and one of the most common cancers of dogs. In UK practices it was newly diagnosed in about 63 of every 100,000 dogs a year, and advanced age, body weight over 30 kg and certain breeds raised the risk¹. Across several European countries the Doberman, Rottweiler, Boxer and Bernese Mountain Dog were predisposed².

The most common form shows as painless swollen lymph nodes: under the jaw, in front of the shoulders, behind the knees. A dog can seem well otherwise, or be tired, thirsty and off its food. Some forms affect the gut, skin or chest instead. A swollen node is easy to sample with a needle, and lymphoma is one of the cancers that most often responds to chemotherapy, which dogs generally tolerate far better than people do¹².

Check the lymph nodes when you groom an older dog of an at-risk breed, and log anything new in the care history.

This is general information, not a diagnosis. Your vet knows your dog.

Sources

1. Incidence and risk factors for the diagnosis of lymphoma in dogs in UK primary-care practice (Pittaway C et al.). Journal of Small Animal Practice, 2019 (peer reviewed). Accessed 2026-09-22.
2. Breed-associated risks for developing canine lymphoma differ among countries: an European canine lymphoma network study (Comazzi S et al.). BMC Veterinary Research, 2018 (peer reviewed). Accessed 2026-09-22.