Lymphoma in Dogs: Signs, Staging and Chemotherapy

By Tailwisp Editorial TeamUpdated October 17, 20263 min read

One of the most common canine cancers often announces itself with a lump you can feel.

What it is

Lymphoma arises from lymphocytes, white blood cells found in lymph nodes, spleen, liver and bone marrow. Several forms exist. The multicentric form, affecting multiple lymph nodes, is most common. Others involve the gut, skin, chest or other organs.

Who is affected

Middle-aged to older dogs are most commonly affected. Golden retrievers, boxers, bulldogs, Rottweilers, basset hounds and some other breeds appear at higher risk, though any dog can develop it. The cause is not fully understood.

Signs

• Firm, enlarged lymph nodes, often under the jaw, in front of the shoulders or behind the knees
• Lethargy and weakness
• Loss of appetite and weight loss
• Increased thirst and urination
• Vomiting or diarrhea in gastrointestinal forms
• Cough or breathing difficulty in chest forms
• Skin lesions in cutaneous forms
• Fever and pale gums

See dog cancer signs.

Diagnosis

Your vet will check lymph nodes and run a fine needle aspirate for cytology, followed by biopsy or flow cytometry to confirm and classify the lymphoma as B-cell or T-cell. Staging uses bloodwork, urinalysis, X-rays, ultrasound and sometimes bone marrow sampling.

Staging

Stages range from I (single node) to V (bone marrow or other organs involved). A sub-stage reflects whether the dog is feeling ill. Staging helps predict response.

Treatment

• Chemotherapy protocols, often using multiple drugs such as the CHOP protocol, given over several months under an oncologist's care
• Prednisone alone, a palliative option that provides short remission but can limit later response to other drugs
• Radiation for localized disease in some cases
• Supportive care: anti-nausea drugs, appetite support, fluids and antibiotics when needed

Most dogs tolerate chemotherapy better than people do, with mild side effects in many cases. Serious reactions can occur, so monitoring is essential.

What to expect

Many dogs with multicentric lymphoma go into remission within days to weeks of beginning treatment. Remission may last months to a year or longer in some, but relapse is common. Outlook varies with type, stage and response. Your oncologist can share typical numbers and what they mean for your dog.

Questions to ask your oncologist

Ask what type and stage your dog has, which protocols are offered, what each costs, how often visits will be needed, what side effects to expect and what the plan is if the cancer returns. Ask what quality of life looks like during treatment.

Supporting your dog at home

1. Give medications exactly as directed.
2. Handle chemo drugs safely by following the clinic's instructions, such as wearing gloves.
3. Watch appetite, stool and energy and report changes.
4. Keep your dog comfortable with soft bedding and gentle activity.
5. Attend every recheck.

Costs and planning

Chemotherapy is a significant commitment. Ask for estimates of the whole protocol and discuss options at various budgets, including palliative care. See dog pet insurance guide.

Quality of life

Check regularly with a scale or log. See dog quality of life scale.

Common mistakes

• Waiting to see if a lump goes away
• Giving prednisone before diagnosis, which can complicate testing
• Skipping rechecks
• Ignoring subtle changes in appetite

Troubleshooting

• My dog is vomiting after chemo: call the clinic.
• Lumps are returning: book a recheck.
• My dog has no appetite: ask about appetite stimulants.

A simple plan

1. Get a prompt diagnosis.
2. Meet an oncologist.
3. Choose a plan that suits your dog and family.
4. Monitor closely.

Real-life examples

A golden retriever's swollen nodes shrink within a week of chemotherapy, and he enjoys many good months. A boxer receives palliative prednisone and several comfortable weeks. A terrier with gut lymphoma is treated with a different protocol. Choices vary.

Making the best of time

Treatment aims to give dogs more good days with minimal side effects.

The takeaway

Lymphoma is treatable but rarely curable. Seek diagnosis quickly and discuss options with an oncologist.

This article is general educational information, not veterinary advice. Every dog is different. If your dog is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.