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 lymphoid tissue of the bone marrow, thymus, spleen, or lymph nodes, the resulting disease is referred to as multicentric lymphoma. Unfortunately, it is a fairly common and deadly form of cancer in dogs. Other forms of lymphoma are less common but do exist, when the 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 as well as 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 this swelling on your dog’s neck on the sides and under his lower jaw, or on back of their legs behind his knee. This may be accompanied by increased thirst and Urination. During your pet’s trip to the veterinarian, a thorough physical examination will be performed and these lymph nodes will be palpated.
If your veterinarian suspects lymphoma, they will most likely recommend a fine needle aspirate. This is a fairly simple procedure where a needle is placed into your dog’s lymph node and a sample obtained for evaluation under a microscope. If a diagnosis of lymphoma is made your veterinarian may recommend further testing to differentiate between T and B cell lymphoma as well as other testing to stage the progression of the disease. Commonly, blood work and ultrasound is performed to help identify how far advanced the disease is at the time of diagnosis.
Currently, there are two distinct 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 period of time. A veterinary oncologist will recommended for your dog and after an initial consultation and staging, treatment 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 progression of disease over time. Currently, the average survival times for T Cell Lymphoma is a 6 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 putting 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 dramatic improvement in your dog, albeit for a much shorter duration than with combined chemotherapy. Please note, 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.