Lymphoma in dogs

isolated dog


  • Lymphoma is a cancer of the immune system.
  • The immune system is active throughout the whole body, and lymphoma can develop in any part of it.
  • Symptoms of lymphoma vary depending on what type it is, where it is, and how aggressive it is.
  • Commonly, the first symptoms of lymphoma include swollen lymph nodes (glands) and excessive drinking/peeing.
  • Treatment is available to extend the life of a dog with lymphoma, but sadly, the condition is eventually always fatal.
  • Contact your vet if you notice your dog has big lymph nodes.

General information

Lymphoma is cancer of the immune system; it can affect any part of it (which runs throughout the whole body), but is most common in the lymph nodes, spleen, bone marrow and intestines. If your dog has lymphoma, their survival time will depend on which type they have, where it is, how aggressive it is, how far it’s spread, and the symptoms it causes.

Lymphoma often develops in middle-aged dogs (6-7 years old) but it occasionally affects puppies.


Symptoms of lymphoma vary depending on what type it is, where it is and how aggressive it is. Possible symptoms include:

Illustration of lymph nodes

The diagram above shows the lymph nodes (glands) you can easily feel in your dog: under the jaw, in front of the shoulder, in the ‘armpit’, in the groin and behind the knee. Click image to enlarge.

When to contact your vet

Contact your vet if your dog has the symptoms above, especially if you can feel big, swollen lymph nodes.

You know your dog best, if they don’t have the exact symptoms listed above but you are still concerned, contact your vet.

Diagnosis - grading and staging

To confirm a diagnosis, decide on the best treatment plan, and predict their survival time, your vet will perform a number of tests to grade and stage your dog’s lymphoma:

  • Grading - tells us how aggressive the lymphoma is
  • Staging - tells us where lymphoma is, and whether it has spread around the body. Staging ranges from (Stage 1) with just one lymph node enlarged, through to the most serious (Stage 5) where the cancer has spread to the bone marrow and other organs.

The tests are likely to involve:

  • X-rays and scans
  • Samples from the tumours
  • Blood tests.

Your vet may need to refer your dog to a specialist veterinary centre for full diagnosis and treatment.

Treatment and outlook

Without treatment

Sadly, without treatment, many types of lymphoma are fatal within a few weeks.

Palliative care

Your vet may advise steroid drugs to reduce symptoms and possibly extend survival time for a few weeks.


Chemotherapy drugs attack cancer cells, slow their growth and reduce tumour size. Chemotherapy can significantly extend your dog’s survival time (from a few months to possibly a year or more), but response varies a lot and is impossible to predict because each case of lymphoma is different. It’s important to be aware, that some types of lymphoma don’t respond well to chemotherapy and even with a good response, your dog won’t be cured; they may live longer than they would have done without treatment, but eventually their cancer will return. Chemotherapy does have side effects, but nowadays these tend to be mild.

It’s very important to consider your dog’s outlook and quality of life when deciding on a treatment path. Your vet will be help you decide what is best for you and your dog.

When to euthanise

Sadly, if your dog is suffering with lymphoma and treatment isn’t helping, it may be kinder to put them to sleep. Many owners find this a very difficult decision to make, which is why your vet is always there to guide and help you through the process of making the decision. Your vet will make sure you make the right decision at the right time. 


Treatment for a poorly dog with lymphoma is often very expensive. Depending on the treatment path, costs can reach thousands of pounds. It’s very important to speak openly to your vet about your finances, the cost of treatment, as well as what you think is right for your dog. There are several treatment options so if one doesn’t work for you and your pet then the vet may be able to offer another.

Consider insuring your dog as soon as you get them, before any signs of illness start. This will ensure you have all the support you need to care for them.

Published: November 2019

PetWise Pet Health Hub – brought to you thanks to support from players of People’s Postcode Lottery 

Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst