Perioperative nutrition in cancer patients.

Cancer patients have the highest incidence of protein-calorie malnutrition seen in hospitalized patients, with significant malnutrition occurring in more than 30% of cancer patients undergoing major upper gastrointestinal procedures. Clinically significant malnutrition occurs as a result of diminished nutrient intake, increased nutrient losses, and tumor-induced derangements in host metabolism. In the absence of adequate exogenous nutrients, the body utilizes endogenous substrates to satisfy the ongoing requirements of both host and tumor for energy and protein. In those patients with malignant obstruction of the gastrointestinal tract, the tumor itself may induce diminished nutrient intake. Present day treatment modalities including gastrointestinal resection, chemotherapy, and radiotherapy compound these metabolic derangements, further increasing the risk of postoperative morbidity and death. The presence of malnutrition in cancer patients has prognostic importance. In a review of more than 3000 cancer patients, DeWys and colleagues identified significantly improved survival in those patients without weight loss compared with those had lost 6% of their body weight (Am J Med 69:491-497, 1980). Other investigators have noted increased postoperative morbidity and mortality associated with malnutrition. Early hypotheses suggested that reversal of weight loss would improve survival. The development and refinements of enteral and parenteral nutrition have provided the opportunity for studying the relationship between nutritional supplementation and postoperative prognosis. Nutrition support is therefore often instituted to improve nutritional status and thereby reduce the risks of postoperative complications. This article addresses the beneficial role of preoperative nutrition therapy in cancer patients.