Doctor, what about supplements to help boost my pet’s immune system? Which ones do you recommend?” I hear this question almost daily as an oncologist battling cancer. I wish I knew the answer. In fact, I know we all wish we knew the answer. But what do we really know about supplements to boost immune stimulation? While there is an incredible amount of information available on the Internet (try Googling “immune stimulants for cancer”—680,000 results appear), there is a paucity of credible information on which to make our decisions. And in the era of evidence-based medicine, few published studies qualify as double-blinded and controlled to help us formulate a decision. Oral Supplements In the past decade, several oral cancer supplements have been marketed for this very purpose. Some of the ingredients have included vitamin E, omega-3 fatty acids, L-arginine, grape seed extract, N-acetyl cysteine, coenzyme Q10 and green tea extract. All have shown some positive effects, albeit some in vitro, against tumorgenesis. Nutritional supplements for cancer treatment will continue to be a controversial part of therapeutic intervention. Antioxidants The theory of inflammation and oxidative damage leading to genetic mutations in susceptible cells is strongly supported, and reduction of inflammation and oxidative damage are viable targets for cancer therapy. Antioxidants such as grape seed extract and vitamin E have been used in people and animals for years. It is important to note, however, that several chemotherapy drugs, the most common being Adriamycin, and radiation therapy exert their effects by the generation of free radicals as a mechanism toward cell death. In these situations, several oncologists (including me) recommend avoidance of these supplements the day before, of, and one day post-chemotherapy. Radiation therapy patients should discontinue supplementation during the course of therapy (sometimes up to four weeks). Omega-3s Research has shown that alterations in the metabolism of carbohydrates, proteins and fat are present in cancer patients, and a role for supplementation of omega-3 fatty acids does exist in treating canine lymphosarcoma. Omega-3 fatty acids may benefit patients by inhibiting enzymes involved in metastasis and reducing secretion of the cytokines TNF-alpha (tumor necrosis factor-alpha), IL-1ß (interleukin-1ß), IL-1alpha, and IL-2, which promote tumor growth. Animal studies also suggest that omega-3 fatty acids inhibit cachexia. Immunotherapy In the traditional sense, the immune system as a pathway for attacking tumorgenesis has been studied for decades. More recent insights into anti-tumor immunotherapy have led to a wave of clinical trials involving true immunotherapy for cancer. Vaccines have evolved from nonspecific immune stimulants, like bacillus calmette-guerin (BCG), to much more specific and potent strategies, some of which generate active immune responses against tumor-associated antigens. Most people are familiar with vaccines that prevent infections like tetanus, polio and measles. These so-called preventive vaccines use the body’s immune system to resist or fight these infections. New kinds of experimental vaccines are now being studied as possible treatments for non-Hodgkins lymphoma. These lymphoma vaccines are not designed to prevent lymphoma, but rather to treat a lymphoma that already exists and therefore are called therapeutic vaccines. Therapeutic lymphoma vaccines are experimental and not yet approved by the U.S. Food and Drug Administration. Clinical trials in people and animals are ongoing. Further understanding of the mechanisms of anti-tumor immunity and identifying target antigens will likely improve these therapeutic strategies and provide a novel mechanism for the future of cancer therapy treatment. Educating Clients Nutritional supplements for cancer treatment will continue to be a controversial part of therapeutic intervention. Our clients look to us as experts for their animals’ medical care. We must distinguish those companies selling snake oils of the new millennium, empty promises and false hope from the companies that are truly providing a quality product with research support to back up marketing claims. It is important that we as veterinarians educate our clients on these products, request quantitative analysis reports from the manufacturers and encourage double-blinded controlled studies so as to forge ahead with justifiable additions to our armamentarium of therapeutics against this dreaded disease. <HOME> Dr. Impellizeri, Dipl. ACVIM (oncology), is medical director of the Veterinary Specialty Center of the Hudson Valley, PLLC, www.vschv.com.
