Lymphosarcoma in Dogs

A fawn boxer dog sleeping on the floor.

 Michael Lofenfeld / Getty Images

Lymphosarcoma, -commonly known as lymphoma, is a cancer of the lymphatic system. This common cancer is more common in certain breeds and luckily has been studied significantly. While chemotherapy is not for every dog, treatment and put dogs into remission and increase their survival time. 

What is Lymphoma?

Lymphoma is one of the most common types of cancer in dogs. Cancer is a scary word but to dismantle cancer it is no more than cells that will not stop diving. Each ell in our body has a job and a life expectancy programmed into it. Cancer cells have their information programmed wrong and will continue to proliferate at the cost of the bodies in which it resides. Lymphoma is a cancer that belongs to a group of specific white blood cells called the lymphocyte. Lymphoma is commonly found in the lymph nodes but it can grow anywhere in the body. It can be localized to one specific area or spread all over the body. 

Lymphoma can develop at any age but it is seen most often in dogs between 6 and 9 years old and there seems to be certain breeds more affected than others. While any dog can develop lymphoma, it is commonly seen in golden retrievers, boxers, bulldogs, and west highland white terriers to name a few. 

Signs of Lymphoma

Most pet parents notice a swelling on their pet and take their pet to the veterinarian. Lymph nodes are commonly felt under the neck, front of the chest, under your dog’s armpits, in their groin, and behind the knee. It is worth noting that lymph nodes can be enlarged due to inflammation elsewhere in the body. During a physical exam when you see your vet feeling around your pets body they are not only checking for lumps and bumps but also feeling the above lymph nodes for any enlargement. 

Depending on how far the cancer has progressed some pet parents my see more pronounced changes like decreased appetite, general lethargy, weight loss, severe gastrointestinal issues, and difficulty breathing

  • Enlarged lymph nodes
  • Loss of appetite
  • Lethargy
  • Weight Loss
  • Vomiting
  • Diarrhea
  • Fever

Causes of Lymphoma

While a diagnosis of cancer for any dog can be devastating the cause of lymphoma is unknown. Lymphoma in dogs is similar to non-Hodgkin’s lymphoma in people. In people, non-Hodgkin’s lymphoma is linked to severe immune suppression such as having an organ transplant. In dogs this link has not yet been proven. While there seems to be prevalence of certain breeds, those genetic links have not been identified.

Diagnosis of Lymphoma

When you bring your dog to the veterinarian they will do tests to diagnosis lymphoma. Without doing diagnostics a vet is unable to tell if a mass or lump is cancerous. Starting with a full exam your vet will feel your pet’s lymph nodes and determine which ones feel enlarged. When a lymph node is enlarged your can take a small sample in the exam room with a needle. In the case of lymphoma, likely a lymph node is sampled using a sampling technique called a fine needle aspirate. The fine needle aspiration is done without sedation or anesthesia and is no more painful that a pet receiving a vaccine. The sample of cells from the lymph node are put on a glass slide, stained to enhance the cell structures, and evaluated under the microscope.  

Your veterinarian my look at the cell samples in their hospital or send it out to a specialty lab to have a pathologist review the sample. When the presence of cancer cells are identified, the veterinarian will “stage” your dog to see how far the cancer has progressed. Staging involves multiple diagnostics to get an overview of what organs have been affected. A common workup includes x-rays of the chest and abdomen, an ultrasound (sonogram) of the abdomen, blood testing that looks at internal organ function, red and white blood cell levels, and urine testing. 

Treatment of Lymphoma

The best bet for increasing your dog’s survival is seeing a board certified veterinary oncologist. Just as in people, when you have a very specific disease you need to see a specialist. Veterinary oncologists have done a three year residency after veterinary school to let them focus on cancer diagnostics, treatments, and palliative care.

The first step is staging your dog and having a veterinarian get a big picture of overall health and the extent of where the lymphoma is. Remember, dogs are walking around and wagging their tails and are oblivious to their own lymphoma in some cases. After your dog is staged, you will have a consultation with an oncologist where they will review your dog’s general health aside from the lymphoma and discuss your options for treatment including side effects such as bone marrow suppression.

Other types of cancers in dog can use surgery or radiation but lymphoma responds to chemotherapy. Chemotherapy is generally given to dogs on a weekly basis with injections. Dogs tend to tolerate chemotherapy well overall but nausea and anorexia and other GI signs can occur. Chemotherapy cannot cure lymphoma but it can put it into remission. Pursuing chemotherapy involved dedication on behalf of the pet parents, not only emotionally and physically but also financially. Sometimes the cost alone can be a reason why a dog will not receive chemotherapy but options to use steroids alone do exist when chemotherapy is not an option. 

Survival times will vary depending on your pet’s overall health and stage of lymphoma but with chemotherapy treatment where dogs achieve complete remission the dogs have an average survival time of 12-14 months. Without treatment the life expectancy in dogs with lymphoma is 1- 2 months. Your oncologist will go through your dog’s individual details and discuss what treatment option would be best for your dog. Even if chemotherapy is not an option, your dog can be kept more comfortable with steroids and other palliative treatments.

Life Expectancy of Dogs with Lymphoma 

You are most likely wondering, after a dog gets diagnosed, how this affects their life expectancy. Unfortunately, the answer is not always clear, and the prognosis depends on multiple factors including how the dog feels, what stage the cancer is, what stage it was when diagnosed, and treatments used. The prognosis with chemotherapy is relatively good, with most dogs experiencing either a partial or complete remission and a life expectancy of around one year, on average.