By Joanne Intile, DACVIM
Lymphoma is a blood-borne cancer of lymphocytes, which are a specific type of white blood cell. It is the most common cancer diagnosed in dogs. There are several forms of lymphoma in dogs, the most common being high-grade lymphoblastic B-cell lymphoma, which closely resembles non-Hodgkin’s lymphoma in people. Lymphoma is one of the most treatable cancers in dogs, and recent developments in targeted therapies, monoclonal antibodies, and bone marrow transplantation could offer the hope of a cure in the future. Whether your dog was recently diagnosed, currently undergoing treatment, or you’re looking for information about disease prevention, you will find the following tips for treating and beating canine lymphoma valuable.
1. Pet your pup!
While you might expect a dog with cancer to show signs of illness, many dogs with lymphoma behave normally. Feeling enlarged lymph nodes may be the only sign something is wrong, and early detection is helpful for ensuring your dog is a good candidate for treatment. Lymph nodes are most readably felt under your dog’s chin, in front of his or her shoulders, and behind the knees. If you’re not sure about where to feel, here is a helpful video showing the location of lymph nodes in dogs. Don’t be afraid to ask your veterinarian for help. If you feel anything suspicious, contact your veterinarian so your dog can be evaluated as soon as possible.
2. Ask your vet for a referral to a board-certified oncologist.
If your primary physician was suspicious you had cancer, they would refer you to an oncologist. The same is true for your dog. Meeting with a veterinary oncologist does not mean you are committing to a specific treatment plan. Rather, this is your opportunity to ask questions about what to expect if your pet were to be treated for his disease versus if he were not, and to talk about what tests could be valuable for learning more about your dog’s cancer. Veterinary oncologists have extensive experience in the diagnosis and treatment of canine lymphoma. They will provide the most up-to-date information and have access to advanced treatment options beyond what is available to a general practitioner. For example, there is a newly approved drug for treating lymphoma in dogs that is currently only available to oncologists and could be an excellent option for your pet.
3. Purchase pet insurance.
While this is not an option to help pay for treatment following a diagnosis, many pet insurance companies will reimburse owners for a portion of the cost of cancer treatment for dogs insured prior to being diagnosed with cancer. Diagnostic tests and cancer treatment costs vary, but typically range from several hundred to several thousand dollars. Owners frequently admit discomfort with the impact that cost has on their decision to pursue treatment. Insurance can relieve some of this burden, allowing them to pursue options they would not have had without coverage. Some pet insurance companies offer “cancer riders” that provide additional reimbursement specifically for cancer care.
4. Don’t start treatment with prednisone/steroids before your appointment with your medical oncologist unless absolutely necessary.
Prednisone is frequently prescribed to dogs with lymphoma at the time of diagnosis, prior to consultation with a veterinary oncologist. Prednisone is a potent anti-inflammatory drug and can also help kill off a certain proportion of cancerous lymphocytes. While this may seem like a good thing to happen while you’re waiting for your referral appointment, there are two main concerns with this approach. One is prednisone administration prior to pursuing definitive treatment could interfere with tests your veterinary oncologist may recommend. Testing routinely includes labwork to look for cancerous lymphocytes in circulation, as well as imaging tests such as X-rays and abdominal ultrasound exams. If prednisone is started prior to executing these tests, the changes consistent with disease may improve or even completely resolve and your oncologist won’t be able to interpret the data correctly. This means they won’t be able to tell you an accurate stage of your pet’s disease.
Secondly, it is speculated that steroids can induce resistance to certain chemotherapy drugs used to treat lymphoma. This means dogs receiving steroids before chemotherapy could have less chance of responding to treatment, and their duration of response could be shorter.
Exceptions to this tip include dogs who are sick from lymphoma (e.g. not eating or having trouble breathing) and require more immediate treatment.
5. Don’t start your dog on any supplements, vitamins, nutraceuticals, or diet changes until you speak with your veterinarian.
It’s human nature to use the Internet to gather information about your pet’s health. A quick search for “canine lymphoma” returns nearly 500,000 hits. An impressive subset of this information is dedicated to the concept of treating dogs with lymphoma with homeopathy or other “natural” substances. Most sites lack evidence-based information proving such data is accurate. The rationale of “it may not help, but it can’t hurt” is false. The absence of a negative side effect does not imply safety—this is what FDA regulation is all about.
Some supplements could potentially negatively interfere with chemotherapy. For example, antioxidants may interfere with the mechanism of action of certain chemotherapy drugs as well as the normal physiologic way tumor cells are broken down by the body. There’s also evidence antioxidants may promote cancer growth. This doesn’t mean antioxidants don’t possess potential benefits, it simply reinforces that they must be used rationally and with appropriate research evidence to support their use.
While there are no known ways to prevent lymphoma in dogs, we do see this cancer in certain breeds more frequently (Golden Retriever, Labrador Retriever, Boxer, Bull Mastiff, Basset Hound, St. Bernard, Scottish Terrier, Airedale, and Bulldog). Owners of these breeds should talk with their veterinarian about what monitoring steps could be useful. Individuals considering owning one of the at-risk breeds should inquire with their breeder (if possible) about any known cancer patterns in their lines.