The first sign of lymphoma you may notice are swellings on your dog’s neck
In some dogs, the signs can be more vague and non-specific
Your vet will need to take some samples to make a diagnosis
If your dog has swollen lymph nodes, your vet may take a fine needle aspirate of them
This may be followed up with biopsies, and other tests such as blood tests and scans
These tests allow us to stage and type the cancer
Lymphoma is a type of cancer that is, unfortunately, reasonably common in dogs. Cancers tend to affect a certain type of cell in the body and the type of cells affected by lymphoma are lymphocytes. These cells are important parts of the immune system and are found throughout the body.
In this article, we look at what symptoms we might see in dogs with lymphoma, and the tests needed to reach a diagnosis.
Pet owners are usually alerted to the problem when they discover large swellings in their dog’s neck. They can look and feel like large golf balls just under the dog’s jawline and they are usually not painful at all.
Other signs include:
Vomiting and diarrhoea
Drinking and peeing more
Unexpected weight loss
Changes in appetite
Pale gums, bleeding and bruising
These signs are not specific to lymphoma, so your vet may rule out other, more common conditions first. Once lymphoma joins the suspect list, your vet will advise more tests.
The least invasive test is called a fine needle aspirate.
This is a simple test to perform if your dog has swollen lymph nodes.
A needle is inserted into the swelling and some cells are sampled.
Your vet may take samples from a few different lymph nodes - this is to ensure the specialist vet at the lab has plenty of cells to examine for evidence of cancer.
Only a small number of cells can be obtained by a needle sample, so it is not uncommon for the results to be inconclusive. If this is the case, and your vet is still worried about cancer, they may suggest taking larger samples from the glands under general anaesthetic, called an excision biopsy.
Even if lymphoma is diagnosed via a needle sample, your vet may still advise that your pet has an excision biopsy. This will allow the lab to better identify what type of lymphoma your dog has, and to grade and start to stage the cancer.
Grading tells us how aggressive a cancer is. Staging looks at whether cancer is present in one or multiple lymph nodes, whether there are affected lymph nodes in one or both body cavities, and whether the cancer has spread to the spleen, liver, or bone marrow.
Your vet may also discuss further investigations such as blood tests, chest x-rays, a scan of your dog’s tummy, and sometimes taking a sample of your dog’s bone marrow.
These tests check for any other big lymph nodes anywhere else that aren’t visible on the outside and look for spread to other organs. This is also part of staging, and helps your vet to plan for potential treatment options and also to be able to tell you what the future looks like for your pet.
Types and Stages
There are two main types of lymphoma, determined by what type of lymphocyte the cancer has affected. These lymphocytes are called B cells and T cells. This information can be helpful as, broadly speaking, B cell lymphoma often responds more readily to treatment than T cell lymphoma but not always. Not all dogs read the textbook!
Lymphoma is staged from 1-5 in dogs, where stage 1 is the least severe, and 5 the most. Severity depends on how much the cancer has spread. They may also be given a sub-stage of ‘a’ or ‘b’, which describes how well your dog is actually coping with the cancer. Substage ’a’ indicates your dog is coping quite well, and having minimal symptoms. Substage ‘b’ dogs may show symptoms such as tiredness, vomiting, diarrhoea or a high temperature. Assigning a stage to lymphoma is helpful when referring to a specialist cancer vet - knowing the stage allows the specialist to tailor the consultation to you and your dog, and discuss the most appropriate treatment options.
The vets at MyDogDoc know just how worrying a diagnosis of cancer can be, and we’re here to offer an understanding ear and support you and your pet whenever you need us.