Lymphoma in Dogs
Lymphoma is a form of cancer of the immune system. Specifically, lymphocytes are a type of white blood cells responsible for fighting infection. When cancer strikes the bone marrow’s lymphoid tissue, thymus, spleen, or lymph nodes, the resulting disease is called multicentric lymphoma. Unfortunately, it is a form of cancer, both fairly common and very deadly in dogs. Other forms of lymphoma are less common but do exist when cancer starts in the GI tract, eye, skin, central nervous system, or thorax. These are called alimentary, mediastinal, or extranodal lymphoma. In the following article, I will discuss multicentric lymphoma and the diagnostic testing and treatment options available.
The first sign of a problem you may notice is simply a non-painful swelling or lump on your dog. Commonly, owners will notice swelling on their dog’s neck on the sides and under their lower jaw or on the back of their legs behind their knees; this is sometimes accompanied by increased thirst and Urination. Your pet will receive a thorough physical exam, during which the vet will palpate its lymph nodes.
If your veterinarian suspects lymphoma, they will most likely recommend a fine needle aspirate; this is a fairly easy procedure where the vet places a needle into your dog’s lymph node and obtains a sample for evaluation under a microscope. If the diagnosis is lymphoma, your veterinarian may recommend further testing to differentiate between T and B cell lymphoma and other testing to stage the progression of the disease. Commonly, blood work and ultrasound are performed to help identify how far advanced the disease has become at the time of diagnosis.
Currently, there are two different treatment plans. The first uses a combination of chemotherapy dogs and steroids. Using this protocol, up to 90% of dogs can achieve full remission for some time. A veterinary oncologist will recommend for your dog, and after an initial consultation and staging, treatment is initiated. Treatment of lymphoma will involve repeated trips for both treatment and monitoring. Routinely, blood work is taken to ensure your pet’s immune system can handle the chemotherapy and ultrasounds to stage the disease’s progression over time. Currently, T Cell Lymphoma’s average survival times are six months, and B cell lymphoma 12 months. Fortunately, dogs tend to tolerate chemotherapy very well, and the hair loss, vomiting, and lethargy seen in humans is much less common, although still possible.
If you decide to put your dog through chemotherapy, and repeated trips to the Oncologists is too much for your dog, even though they are caring, wonderful, Veterinarians, there is another treatment option. Starting higher doses of oral steroids can result in a dramatic improvement in your dog, albeit for a much shorter duration than with combined chemotherapy. However, please note that once oral steroids alone have been started, chemotherapy is no longer successful, and this takes that option off the table moving forward.
If you suspect your dog has lymphoma, we recommend scheduling an appointment with a member of our veterinary team for evaluation, testing, and a more thorough discussion of treatment options.
Jeffrey Stupine, V.M.D.
World of Animals Veterinary Hospitals