Cancer is an unfortunately common problem in pets. The most common type of cancer in pets is lymphoma, also known as lymphosarcoma. Lymphoma is cancer of the lymph system, which consists of lymph nodes and vessels. The lymph system is responsible for immune responses to foreign invaders, such as bacteria and viruses. Lymphoma in our pets is named after the organ targeted by the disease. In cats, the majority of lymphoma is intestinal, (a subject we’ll discuss in a future blog), but in dogs, more than 80% of lymphoma cases are multicentric, meaning affecting all of the lymph nodes.
When the lymph cells become cancerous, they cause swelling of the lymph nodes. In affected dogs, the swelling is quite dramatic, and you will notice swellings at your dog’s neck, chest and behind the knees. These are the lymph nodes that are most easily felt on the outside of your dog, but all lymph nodes, including internal nodes, are enlarged.
Multicentric lymphoma is devastating, as it seems to appear out of nowhere and carries discouraging statistics with it. Without treatment, affected dogs succumb to the disease within four to eight weeks. Once a preliminary diagnosis of multicentric lymphoma is made, your veterinarian will want to “stage” the disease, or see how far (if at all) it has spread. X-rays, ultrasounds, lymph node biopsies and bone marrow biopsies are all useful to determine the extent of the disease and the best way to tackle treatment. Thankfully, Petplan pet insurance can cover cancer treatments, letting you focus on getting your pet comprehensive tests and treatment, not the vet bills.
Several chemotherapy protocols exist for multicentric lymphoma. Before we go any further, it’s important to address this scary word: chemotherapy. We are probably most familiar with chemotherapy’s effect on humans, where it can cause nearly unbearable side effects, including severe gastrointestinal repercussions and hair loss. In our pets, this does not happen. Well, it does not happen frequently, I should say. Gastrointestinal side effects are rare. In fact, less than 7% of patients need treatment or hospitalization for these types of side effects. And while your pet may lose his whiskers, substantial fur loss will not occur.
Your veterinarian may be comfortable offering chemotherapy treatment at his or her clinic, or may refer you to a veterinary oncologist. The goal of lymphoma treatment is to achieve remission, meaning that the cancer is not detectable in your pet after treatment. Remission is highly possible in lymphoma – about 75% of our patients achieve remission. There are cases of multicentric lymphoma that have been cured, but they are rare.
A more realistic goal for the treatment of multicentric lymphoma is to provide a comfortable life for your dog as long as possible. The median survival time for most dogs on chemotherapy is one year, with 25% of patients surviving two years.
Multicentric lymphoma is not the only type of lymphoma that occurs in dogs, but it is the most common. Lymphoma of specific places, such as the gastrointestinal tract, mediastinal area of the chest and skin or eyes also occurs. Each of these specific types of lymphoma have their own treatment protocols that can be addressed by your veterinarian.