Lymphoma, also known as lymphosarcoma, is a malignant cancer of the lymph system (a vital part of the immune system that includes the lymph
nodes, the thymus, liver and the spleen). Lymphoma can grow wherever there is lymph tissue, which are most organs of the body. Signs of lymphoma vary depending on the location of the tumor; however, 80% of canine lymphoma is “multicentric,” which means several sites throughout the body.

Typically, lymphoma occurs in middle aged and older dogs. As with all cancers, early diagnosis and treatment offer the best prognosis. Regularly check your Leonberger for enlarged lymph glands, the earliest sign of the disease. In more advanced stages, there will be loss of appetite, weight loss and gastrointestinal upsets. Diagnosis is confirmed by biopsy or needle aspiration.

Treatment is conducted weekly, with several chemotherapy drugs, and continues for approximately eight weeks; then treatments are at two-week intervals for six months. Remission rates up to 90% have been achieved for survival periods of one -two years or longer. A recent double blind, randomized study designed to evaluate the value of polyunsaturated fatty acids in combination with doxorubicin chemotherapy as a treatment protocol, concluded that the addition of fatty acids increased the disease free interval and survival rates of dogs in the study. Dogs do not suffer the same adverse side effects from chemotherapy that affect people. 

Unlike cat lymphoma, canine lymphoma does not appear to be caused by a virus. A case-control study to determine a link between environmental pollutants and an increased risk for canine lymphoma found two variables positively and independently associated with the disease, namely residency in industrial areas and the use of chemicals by the dog owners. In epidemiologic studies, lymphoma has been associated with exposure to chemicals such as phenoxyacetic acids; chlorophenols; dioxins; organic solvents including benzene, polychlorinated biphenyls, chlordanes; and immunosuppressive drugs. Experimental evidence and clinical observations indicate that these chemicals may impair the immune system.

A National Cancer Institute study suggests that contamination of drinking water with nitrate, a chemical found in fertilizers, has been linked to an increased risk of lymphomas, particularly in agricultural areas. In the human population, cancers of the lymphatic system have increased by 75% since 1973.

Please see the Canine Cancer Research Underway page.

Please don't forget to join us in a quest for more information to save lives. The Leonberger Club of America has a Cause of Death Registry which will provide that information.  Fill out a form for any Leonberger that you've lost:  Cause of Death Registry Form

Last updated 08/01/2017 .
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