Oncology Highlight: Canine Lymphoma

Dogs can develop many different types of cancer. Canine lymphoma accounts for up to 24% of all dog cancers, and is the most common cancer type arising from hematopoietic cells (i.e., immature blood cells). If your dog has been diagnosed with lymphoma, you likely have many questions about their cancer type, and their long-term prognosis. The AVES oncology department commonly treats canine lymphoma, and can guide you through your pet’s cancer journey. From diagnosis and staging, to treatment and monitoring, we have vast experience successfully managing canine lymphoma cases, and would be honored to help your beloved companion. Here, we answer the most common questions about this cancer type.

What is canine lymphoma?

Canine lymphoma is a type of cancer caused by the uncontrolled replication of lymphocytes, a white blood cell type that circulates in the bloodstream and organizes in groups in various body structures, including the lymph nodes, bone marrow, spleen, and thymus. This unchecked cell growth can enlarge affected tissue, affect organ function, and cause generalized illness. Why canine lymphoma develops is typically unknown, despite many theories, including a virus, chemical exposure, genetic predisposition, and chromosomal abnormalities.

What lymphoma types can affect dogs?

Lymphoma development is typically limited to a specific lymphatic cell type and location, rather than all body lymphocytes multiplying out of control. Your dog’s lymphoma may be categorized as one of the following types:

Multicentric — Comprising approximately 85% of all canine lymphomas, multicentric lymphoma causes generalized, non-painful lymph node enlargement.
Gastrointestinal (GI) — Lymphatic tissue lining the GI tract can be affected, and accounts for approximately 7% of canine lymphomas.
Cutaneous — Lymphoma that affects the skin often begins as a rash, and then progresses to large, crusting, hairless skin lesions. Cutaneous lymphoma accounts for approximately 6% of canine lymphomas.
Leukemia — Lymphoma affecting circulating lymphocytes or the bone marrow is considered a type of leukemia.

Your dog’s lymphoma may be further subclassified as T-cell or B-cell lymphoma, depending on the lymphocyte type involved.

What are canine lymphoma signs?

Dogs with lymphoma develop signs consistent with the body organs or systems the cancer affects. Generalized lymph node enlargement, which can be felt as swellings below your pet’s jaw, near their armpits, behind their knees, and in their groin, is the most common multicentric lymphoma sign. Your pet may also display generalized illness signs, including:

Weakness or lethargy
Decreased appetite
Fever
Dehydration

Vomiting and diarrhea often accompany GI lymphoma, whereas skin lesions are seen with cutaneous lymphoma.

How is canine lymphoma diagnosed?

Your primary care veterinarian may run diagnostic tests, or refer you to a veterinary oncologist, if they suspect your dog has lymphoma. A multicentric lymphoma diagnosis involves collecting cells from an enlarged lymph node via needle or surgical biopsy, and microscopically examining the cells for changes consistent with lymphoma. If your dog has another lymphoma form, testing specific to the organs affected will be performed, such as a GI or skin biopsy. After a generalized diagnosis, your dog’s lymphoma will be staged to determine how far the cancer has advanced, and the extent of cancer involvement. Staging involves diagnostic tests that may include:

Blood work
Urinalysis
X-rays
Ultrasound
Molecular analysis of cancer cells

How is canine lymphoma treated?

Most canine lymphomas are treated with a combination of chemotherapy medications, although radiation, immunotherapy, and other treatments may be included in a multimodal treatment plan. Our oncology team will evaluate your dog’s lymphoma type, location, and stage, as well as their overall health and lifestyle, and recommend a treatment protocol that will offer the best chance for a positive outcome.

What is the prognosis for canine lymphoma?

Most dogs with lymphoma respond well to treatment, and their cancer can be put into remission. Treatments are not typically expected to cure canine lymphoma, but they can allow additional months or even years with your companion. Dogs typically experience only minor or no treatment side effects. They often have no idea they are sick, allowing them to enjoy the extra time with their families.

If your primary care veterinarian suspects your dog has lymphoma, contact us to discuss the best possible future for your closest friend.