Nutritional support and cancer cachexia. Evolving concepts of mechanisms and adjunctive therapies.

Despite the widespread employment of intravenous feeding in patients with cancer cachexia to improve outcome, conflicting data exist regarding the efficacy of such therapy in addressing metabolic alterations secondary to immobility, malnutrition, and disease-specific processes. Persistence of distinct abnormalities of body and tissue integrity and peripheral tissue plasma inter-organ nitrogen flux imply the need for anabolic agents to enhance the therapeutic effects of parenteral nutrition. This article focuses upon potential anabolic agents such as chronic submaximal exercise, hormonal augmentation, pharmacologic intervention, and variations in substrate composition. Finally, the immunologic, metabolic, and endocrine consequences of bypassing the gastrointestinal tract are considered and related to the limited efficacy of current total parenteral nutrition regimens.