Hearing from the vet that your dog has been diagnosed with lymphoma can be scary. No dog parent wants to hear that their pup has cancer! However, not all hope is lost, as lymphoma is one of the more curable types of cancer in dogs. Learn all about this disease, how to keep a watchful eye out for it, and what to do once your dog starts showing signs.

By Deb M. Eldredge, DVM
November 05, 2020
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Lymphoma is one of the most common cancers in dogs, accounting for up to a quarter of all canine cancers. It comes in four forms, but up to 85% of all lymphomas in dogs are the multicentric form (two or more separate tumors) with enlarged lymph nodes throughout your dog’s body.

What Causes Lymphoma in Dogs?

Lymphoma is a cancer of the lymphocytes which are part of your dog’s immune system. There are B cell and T cell versions. The B cells make antibodies to respond to infection, while the T cells are also known as “killer cells” for destroying foreign invaders. Dogs with B cell lymphoma have a better prognosis in general.

Identifying Signs and Symptoms of Lymphoma in Dogs

With multicentric lymphoma, the first sign families often notice is enlarged lymph nodes. These might be under the jaw, in front of the shoulders, or behind the stifles in the rear legs. These swellings can be up to the size of a golf ball and feel firm, but not rock-hard. They’re also not painful, so you may not observe signs of illness from your dog until you feel for those enlarged lymph nodes. The lymph nodes can swell from infection response as well as cancer, so it’s important to get any swelling checked out by your vet to determine the cause.

Dogs with lymphoma tend to feel fine at first, so you may not notice any other signs of illness. An exception is that if your dog’s blood calcium levels rise, he may lose his appetite, act lethargic, and possibly drink more water due to potential kidney damage. Unfortunately, dogs with increased calcium (hypercalcemia) have a poor prognosis.

Dogs with the intestinal or alimentary form of lymphoma, which is the second most common form of this cancer in dogs, will have vomiting and/or diarrhea, may lose weight, and don't want to eat.

How To Prevent and Treat Dog Lymphoma

There are some dog breeds that seem to be predisposed to lymphoma. These include golden retrievers, boxers, Rottweilers, and Bernese mountain dogs, but any dog can get lymphoma. The first dog I ever treated for lymphoma was a small terrier mix. 

Older dogs are at higher risk and some recent studies have looked into the possibility that spayed and neutered dogs (especially in some breeds such as golden retrievers) may be at higher risk of developing this cancer. Though more research is needed to know this for certain.

Since lymphoma is typically a widespread disease in your dog’s body, chemotherapy is usually the treatment of choice. Dogs tend to handle chemo treatments better than humans and with fewer side effects. One of my own dogs had lymphoma and went through chemotherapy. He never missed a meal and felt great about 90% of the time, wanting to do all his normal activities.

Credit: SariJuurinen / Getty

It is important that if you plan to do chemotherapy that you do NOT give your dog prednisolone unless it is part of the treatment protocol recommended by your veterinarian. It can interfere with your dog’s treatment.

While you may have an initial visit with a veterinary oncologist to decide on the exact chemotherapy protocol to use, treatment can be done by your regular veterinarian. Your veterinarian or the veterinary oncologist (if you work with one) will also guide you as to what supplements might be beneficial, which ones to avoid, and the ideal diet for your dog.

Prognosis for Dogs Living with Lymphoma

Prognosis for dogs with lymphoma will vary. If your dog has the B cell version, his prognosis is generally better. The same is true if his blood calcium levels are normal at the time he is diagnosed. Dogs whose only sign is enlarged lymph nodes tend to do better than dogs who are starting to show signs of illness.

Dogs with no treatment will likely live 6 to 8 weeks. Dogs just given prednisolone (but no chemo) often do well between 2 to 4 months. Dogs who respond right away to chemotherapy (their lymph nodes shrink early on) tend to do best. While these dogs may go out of remission at about a year or so, they often respond to a second set of chemo to gain more quality time. If your dog is diagnosed with lymphoma, that doesn’t mean all hope is lost! My own dog responded immediately, and never went out of remission, passing away three years later from another ailment.

One of the best ways to ensure your dog has the best quality of life possible, regardless of ailment, is to make sure you are taking your dog to the vet regularly for check ups, carefully observing his behavior at home to make sure you notice any changes early, and doing self exams in between vet visits to feel your dog’s body for unusual lumps and bumps.