09/06/2026
Lymphoma is one of the most commonly diagnosed cancers in dogs, but it is not one single disease. It represents a group of cancers involving lymphocytes, the white blood cells that play an important role in the immune system.
The most common presentation in dogs is multicentric lymphoma, which typically causes enlargement of multiple lymph nodes. Other forms can develop within the gastrointestinal tract, chest, skin and other organs. Lymphoma can also be further classified by characteristics such as whether the cancer originates from B cells or T cells, which can influence its biological behaviour, treatment response and prognosis.
One reason awareness is so important is that some dogs with lymphoma may initially seem completely well. A dog parent may first notice a firm, painless swelling under the jaw, in front of the shoulders, in the groin or behind the knees. Other dogs may develop decreased appetite, weight loss, lethargy, vomiting, diarrhea or breathing difficulties depending on where the disease is located.
Diagnosis often begins with a fine needle aspirate of an enlarged lymph node, followed by additional testing when necessary to determine the type and extent of disease.
Canine lymphoma is generally considered a systemic cancer, which is why chemotherapy is an important treatment for many dogs. Many dogs with high grade multicentric lymphoma can achieve remission with combination chemotherapy. Remission, however, is not the same as cure. It means detectable evidence of the cancer has disappeared following treatment, and relapse can occur.
During Blood Cancer Awareness Month, we’re sharing this information because knowing what to look for matters. Get familiar with where your dog’s lymph nodes are located. Pay attention to unexplained lumps and persistent changes in appetite, weight, energy or behaviour, and have abnormalities assessed by a veterinarian.
Awareness cannot prevent every cancer, but it can help pet parents recognize when something needs to be investigated.
Wuff’s Canine Health Clinic
Educational information only. This content does not replace veterinary examination, diagnosis or oncology treatment.
