What is Lymphoma in Dogs
Lymphoma is a type of cancer that affects lymphocytes, which are white blood cells involved in the immune system. In dogs, it most commonly affects the lymph nodes (glands) but can also affect the spleen, liver or skin.
It is one of the most commonly diagnosed cancers in dogs and is seen most often in older dogs. Some breeds are more frequently affected, although lymphoma can occur in any dog.
Lymphoma can progress at different rates depending on the type, and treatment such as chemotherapy may help control the disease and improve quality of life for a period of time.
Written by Gillian Burkhill, Veterinary Surgeon, Animal Trust Vets CIC | Published May 2026 | Review date May 2029 | This advice is for UK pets only and is not a replacement for seeing a vet
Symptoms of Lymphoma in Dogs
Symptoms of lymphoma in dogs can vary depending on where the disease is affecting the body, but commonly include:
Enlarged lymph nodes (often noticed as firm swellings under the jaw, in front of the shoulders or behind the stifles)
Weight loss
Lethargy or reduced energy levels
Increased thirst or urination
Vomiting or diarrhoea (more common with gastrointestinal lymphoma)
Coughing or breathing difficulties (if lymph nodes in the chest are affected)
Skin changes or lumps (in cases of cutaneous lymphoma)
Some dogs may initially appear otherwise well apart from enlarged lymph nodes.
When to contact your vet
Contact your vet if you notice any unexplained swellings (particularly enlarged lymph nodes), weight loss, reduced appetite, lethargy, or other ongoing changes in your dog’s health.
Seek urgent veterinary attention if your dog is struggling to breathe, has a swollen abdomen, is repeatedly vomiting, collapses, or becomes suddenly very unwell, as some cases of lymphoma can progress quickly or cause serious complications.
Diagnosis
Your vet may recommend a physical examination, blood tests and sampling of enlarged lymph nodes to help diagnose lymphoma. This may be done using a fine needle aspirate, where a small sample of cells is taken using a needle.
In some cases, a surgical biopsy may be needed to confirm the diagnosis or provide more detailed information about the type of lymphoma.
Imaging such as X-rays or ultrasound may be used to assess internal lymph nodes and organs. Further tests may be recommended to help stage the disease (determine how far it has spread) and grade the lymphoma, which can help guide treatment planning.
Treatment of Lymphoma in Dogs
Treatment for lymphoma in dogs usually aims to control the disease and improve quality of life for as long as possible.
Chemotherapy is the most common treatment and is generally well tolerated in dogs, with many experiencing relatively mild side effects. The exact protocol used may vary depending on the type and stage of lymphoma.
Supportive care, including medications to manage symptoms such as vomiting or loss of appetite, may also be needed.
Treatment plans are tailored to the individual dog and the type of lymphoma diagnosed.
Prevention of Lymphoma in Dogs
There is no known way to prevent lymphoma in dogs. It is a cancer that develops spontaneously, and most cases occur without a clear underlying cause.
Regular veterinary check-ups and prompt investigation of any unexplained swellings, weight loss or ongoing illness can help with earlier detection and treatment.
Outlook
The outlook for dogs with lymphoma varies depending on the type of lymphoma, how advanced it is at diagnosis, and how well it responds to treatment.
With treatment such as chemotherapy, many dogs can achieve remission, where the cancer is controlled and signs improve for a period of time. However, remission is not the same as a cure, and relapse is common.
Ongoing monitoring and follow-up care are important to help manage the condition and adjust treatment as needed.