Lymphoma in Dogs: Symptoms and Treatment

Dr. Jason Gagné, DVM, DACVIM
By Dr. Jason Gagné, DVM, DACVIM
Updated: 5/14/20242-4 minutes
A young boy pets his dog's face

Dog lymphoma can seem like a scary diagnosis for your pet. It’s a progressive and often fatal illness, and the thought that your canine friend might be suffering from it is tough for any pet owner. But it’s important to have as much information as possible about what this illness means, which symptoms you need to pay attention to, and once you get to the vet’s office, what to expect when it comes to diagnosis and treatment. 

Keep reading to find what you need to know about canine lymphoma.

What is Lymphoma in Dogs?

Lymphoma is the name given to a group of different types of dog cancer typically affecting the lymphatic system. The cells in the lymphatic system, called lymphocytes, are responsible for fighting off infections and are located throughout the body, but they appear in higher concentrations in certain places. This is why lymphoma is usually found in parts of the lymphatic system, such as the bone marrow, spleen, intestinal tract, or lymph nodes.

However, lymphocytes travel everywhere in the body, which means that specific organs outside the lymphatic system—such as the skin, the eyes, or the nervous system—can also be affected in rare cases.

What Are the Types of Lymphoma in Dogs?

The different types of lymphoma cancer in dogs have been named based on the part of the body where they appear. So, if your dog is diagnosed with this illness, you might hear the vet talking about one of these four types of lymphoma in dogs.

Peripheral Lymph Node Lymphoma

As the name implies, this type of lymphoma is typically confined to the peripheral lymph nodes. This is one of the most common forms this illness takes, and it manifests most obviously through enlarged lymph nodes.

GI Lymphoma

If the lymphoma appears somewhere in the gastrointestinal tract, this means your dog is suffering from alimentary lymphoma. Clinical signs include weight loss, vomiting, and diarrhea.

Mediastinal Lymphoma

The lymph nodes in the chest can also swell due to lymphoma. In this case, the condition is called mediastinal. However, this is a rare form of lymphoma in dogs.

Extranodal Lymphoma

If your dog’s lymphoma is found in areas outside the lymphatic system, this means they are suffering from an extranodal case of the illness. The skin, the eyes, the kidneys, and the nervous system can be affected.

What Are the Symptoms of Lymphoma in Dogs?

Canine lymphoma can affect different organs, making the symptoms difficult to pin down. But generally, owners should look out for a few telltale signs of lymphoma: 

  • Large lymph nodes 
  • Weight loss 
  • Lethargy 
  • Vomiting 
  • Loss of appetite 
  • Difficulty breathing

Dog Lymph Nodes

Swollen lymph nodes are one of the symptoms of dog lymphoma. But you may be wondering where exactly the lymph nodes are located and how you can tell when they’re unusually large.

There are many lymph nodes throughout the body, but the easiest ones to access and check are located under the jaw, behind the knee and in the armpit and groin areas. These swollen nodes feel like a large, firm mass under the skin.

Before you check your dog, know that finding a swollen lymph node doesn’t necessarily mean your pet is suffering from cancer. Inflammation in the body can lead to swollen lymph nodes as well. This is why it’s important to get all the necessary tests the vet recommends to learn what is actually happening in your dog’s body. 

How Common is Lymphoma in Dogs?

The prevalence rates for canine lymphoma range from 13 to 114 per 100,000 dogs at risk. Although environmental factors may play a role, studies have shown that certain breeds have a higher risk of developing lymphoma. These breeds include, but are not limited to, Dobermans, Rottweilers, and Boxers.

It’s important to keep in mind that this is often a treatable form of cancer, which can be kept under control with the appropriate care, allowing your dog to enjoy their remaining time alongside you.  

Is Lymphoma in Dogs Hereditary?

Since certain breeds seem to be more affected than others, there may be a slight genetic component to lymphoma. However, lymphoma can occur in dogs of any breed and is thought to be influenced by various factors, including genetic susceptibility, immune compromise, and environmental triggers, like exposure to certain toxins, viruses, or bacteria.

How to Diagnose Lymphoma in Dogs

If lymphoma is suspected, your dog will likely go through a series of tests. With such a systemic illness that can spread pretty much anywhere in the body, the vet will often use X-rays and ultrasound scans to identify any unusual masses. Blood tests will likely also be part of the diagnostic process, as well as samples from any tumors found.

Your vet will also tell you what stage of lymphoma is present in your dog. This can be one of five stages, with stage one meaning that a single lymph node has been found, and stage five being the most serious one in which multiple organs have already been affected. 

Treating Dog Lymphoma

Although canine lymphoma can’t be cured, it can be treated. This means that the aim will be to achieve a reduction of tumor size or prevention of further growth, also known as a remission. Some or all of your dog’s symptoms may disappear, but the cancer might still be present in the body. 

The most common treatment for dogs with lymphoma is chemotherapy. Luckily, the side effects are not always as worrying as they are in humans, with most dogs experiencing neither hair loss nor feeling ill. The type of chemotherapy used, and the frequency of treatments, depend on your dog’s particular diagnosis. Certain types of lymphoma won’t respond to chemotherapy, so surgery or radiation therapy may be advised if chemotherapy is not an option. 

Lymphoma in Dogs Survival Rate

In most cases, lymphoma in dogs will eventually progress to become a deadly illness. The aim of offering your dog the most beneficial treatment is to improve your pet’s quality of life.

Chemotherapy can put the cancer in remission for 10 to 12 months, on average. But eventually, lymphoma will often return, and a second remission is typically more difficult to achieve.

Sometimes pet owners might choose not to offer their dog any treatment. Without treatment, the pet’s survival rate is typically weeks depending on the severity of the illness. 

It’s important to be emotionally prepared for an honest conversation with your vet regarding the survival rate for your dog’s particular type of lymphoma and its current stage so you can choose the best and most comfortable option for your best friend.

What is the Life Expectancy of a Dog With Lymphoma?

A dog suffering from lymphoma can live anywhere from a few weeks to a few years, depending on the type of lymphoma, its stage, the dog’s health, and the recommended treatment. There are many effective treatment options currently available for our canine friends, and chemotherapy, radiotherapy, and immunotherapy can successfully give your dog more time with you.

Lymphoma is a complex, progressive, and often an eventually fatal illness. But with help from a veterinary professional and a focus on your dog’s quality of life during this tough time, you can decide what’s best for your pet and keep them happy for as long as possible.

For more expert tips on your dog’s health, explore our other dog health symptoms and issues articles.

Related articles

A Basset Hound with droopy, red eyes
Is it an allergy, an injury or a disease? What is causing your dog’s eyes to become bloodshot? Here are some of the possible answers.
A little girl holds her smiling black lab close
A woman holds her small dog with wet eyes close
MyPurina App - woman with dog

Reward Yourself with myPurina

Earn and redeem rewards for Purina products with the myPurina app.