Enteral versus parenteral nutritional support in cancer patients.

There are many theoretical and practical advantages to enteral rather than parenteral administration of nutrients. However, it is unlikely that enteral supplementation of nutritional intake as presently practiced will be successful as a primary therapy for most patients with the cancer cachexia syndrome. The most likely role of enteral nutritional support (ENS) is in conjunction with other therapies. This modality deserves evaluation in surgery with curative intent. Changes in diet are effective in reducing the gastrointestinal symptoms of abdominopelvic irradiation, but the effect of ENS on the hematologic toxicity of radiation therapy and on response rates and survival is unclear. Elemental diets can reduce the gastrointestinal toxicity of conventional doses of 5-FU, but they worsen the mortality and hematologic toxicity of higher doses. Factors such as protein, fat, and carbohydrate sources, degree of hydrolysis of protein, lactose content, and timing of dietary manipulations are important in evaluating the response to ENS.