When we hear the word “cancer”, we all have someone who we think of. It is very difficult to find someone who has not been affected by this disease in anyway, as we can all think of special people in our lives who are currently undergoing chemotherapy, who are in remission, and those who we have lost. I personally have lost a grandfather to esophageal cancer and have other family members currently undergoing radiation therapy. While we continue to make great strides in the fight against cancer in the human world, we have also been making progress for our four-legged friends. Although there are many different types of cancers that exist, we tend to see certain types much more frequently than others. Canine lymphoma is one of those cancers, making up roughly 15-20% of new cancer diagnoses.
Lymphoma is defined as uncontrolled proliferation of neoplastic lymphoid cells. Lymphoid cells, mostly B-cells and T-cells, exist in the body as part of the immune system to fight off disease. These cells travel throughout the body to help fight disease and infections in various areas, thus making lymphoma a complex cancer as it can travel throughout the body (metastasize) easily and have many different areas of origin. The most common location of lymphoma in dogs is in the lymph nodes (multi-centric lymphoma), although we can see this disease present in the gastrointestinal tract, skin, bones, brain, mouth, and even the eyes.
When performing a physical exam on your dog, your veterinarian will likely feel various locations to evaluate your dog’s lymph nodes, such as under their neck, their chest, and behind their knees. These lymph nodes can become very enlarged in lymphoma, with most owners noticing swelling under their pet’s neck and pet’s becoming uncomfortable. Your veterinarian may aspirate your dog’s lymph nodes with a needle to look for these abnormal B-cells and T-cells under the microscope, or may even perform a biopsy if needed. If lymphoma is confirmed or suspected, your veterinarian may take more samples or perform imaging (radiographs and ultrasound) to evaluate and classify the stage and type of lymphoma present.
Due to the fact that lymphoma is a disease of cells that spread systemically throughout the body, our best option in fighting this cancer is chemotherapy. Chemotherapy, however, is very different in canines in comparison to humans. Although dogs do have their immune system suppressed by the drugs used and can have some gastrointestinal discomfort, it is very rare to see hair loss, lethargy, or the need for hospitalization as we see in humans. Many different forms of chemotherapy exist, ranging from NSAID’s and steroids to weekly intravenous injections. The choice of chemotherapy used should always depend on the individual patient.
New and promising drugs continue to be developed in our fight against canine cancers. Pets usually reach remission, although it is for a shorter time than achieved in humans (usually 6-9 months), but ultimately lymphoma does prove to be fatal. Despite a lymphoma diagnosis, there are many different ways to assure these patients continue to feel well and have a good quality of life. As always, ensure that your pet has annual examinations with your veterinarian, and if you ever have concerns do not hesitate to contact your local veterinarian.