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| ACVN NutritioN Notes 52 today's Veterinary Practice July/August 2014 tvpjournal.com syndrome is: • Associated with an underlying disease, anorexia, inflammation, insulin resistance, and increased lean muscle breakdown 5 • Linked to tumor-disease driven changes in carbohy- drate, lipid, and protein metabolism as a consequence of altered cytokine activity. 4 Cancer cachexia is observed in approximately 50% of human cancer patients 4 and, although the incidence rate in pets is not reported, it is considered to be similar based on clinical observations. TREATMENT IMPACT ON NUTRITION Multimodal therapy for veterinary cancer patients is con- sidered the current standard of care. Surgery, chemo- therapy, and radiation therapy are commonly utilized, but can have deleterious direct and indirect effects on the nutritional status of the patient. 6-8 Table 1 summarizes the major nutritional concerns associated with these therapies. TUMOR IMPACT ON NUTRITION Presence of a tumor results in alterations of a patient's nutrient metabolism. Research suggests that rapidly grow- ing tumors: • Preferentially utilize glucose from dietary carbohy- drates (CHO) as their major fuel source • Require protein to support metabolic pathways • Are subsequently less efficient at utilizing dietary fats to support growth. Alternatively, slow growing tumors: • Preferentially utilize fat (lipids) as their major fuel source • Upregulate lipoprotein lipase production, promoting entry of fatty acids into tumor cells for metabolism • Have reported de novo synthesis (lipogenesis) of fatty acids. The omega-3 fatty acids—eicosapentaenoic (EPA) and docosahexaenoic (DHA)—have reported antitumorigenic (models in humans, rodents, cats, and dogs) and antica- chectic (models in humans and rodents) functions. 9-11 Select amino acids are essential to support tumor cell functions, as is the case in non-neoplastic cells. Table 2 summarizes the most important amino acids in tumor cell metabolism. 12 Further scientific investigation is needed to determine the precise balance of amino acid–protein in- take for specific patients. Dietary CHO restriction results in glucose deprivation of tumor cells, which limits hydroperoxide detoxification in these cells, rendering them more susceptible to oxidant- induced cytotoxicity. 13 Avoid dietary antioxidant (AOX) supplementation because it can "detoxify" damaging oxidant species in both normal and neoplastic cells, preventing tumor cell devital- ization and destruction. table 1. anticancer therapy impact on nutritional Status TREATMENT MODALITY IMPACT ON NUTRITIONAL STATUS SURGERY • Acute stress response (acute phase proteins, inflammatory mediators, hypermetabolism) • Anorexia-hyporexia, malabsorption • electrolyte imbalances, development of hyperglycemia • Gi alterations (diarrhea, nausea, bloat, regurgitation, vomiting) CHEMOTHERAPY Cytotoxic and Immunotherapy • Anorexia, food aversion • Diarrhea, nausea, and vomiting • Dysbiosis • Fatigue, immunosuppression Hormonal • edema • Hypercalcemia, hyperglycemia • Nausea, vomiting RADIATION Head–Thorax • Anorexia, food aversion • Dysphagia, esophagitis • Fatigue, immunosuppression Abdominal– Pelvic • Abdominal pain, bloat, and flat- ulence • Diarrhea, nausea, and vomiting • Gastric ulceration, Gi inflammation • Maldigestion, malabsorption Extremities • Protein loss, inflammation due to radiation-associated burns • Anorexia–hyporexia associated with limb pain/discomfort APPROACH TO NUTRITIONAL SUPPORT The ACVN recommends assessment of the patient, the food (diet), and the feeding method as a stepwise, integrated, and individual approach to nutritional support. Taken together, the patient's cancer diagnosis, treatment protocol, prognosis, and nutrition status category will aid in developing an optimal nutritional support plan. This ap- proach is summarized in the table, Feeding Guidelines Based on Nutritional Status for Dogs & Cats with Cancer, available at tvpjournal.com/resources.asp#resources. Patient Assessment Assessment of the patient is based on physical examina- tion, clinical history, dietary history, and diagnostics; these findings can be translated into one of 3 nutritional status categories: 3 1. Well nourished 2. Borderline or at risk for becoming malnourished 3. Significantly malnourished. turn to page 56 for this article's associated in-Clinic Form— Step-by-Step: Feeding the Pet with Cancer.