ABSTRACT
Animal studies have clearly demonstrated that spontaneous tumor development and growth of established tumors can be stimulated during periods of exogenous nutrient administration. Protein/calorie deprivation significantly reduces spontaneous tumorigenesis and carcinogen-induced tumor development in animal models. Refeeding can stimulate spontane ous and carcinogen-induced malignancies in many tumor models. Increased caloric and dietary fat intake are particularly associated with an increased incidence of spontaneous tumorigenesis. Stimulation of growth kinetics of established tumors can occur following enteral or parenteral nutrient administration. Acceleration of tumor growth has been demonstrated by objective increases in tumor volume, tumor mitotic activity, H3-thymidine labeling index, tumor pro tein synthesis, and increased S-phase and aneuploid tumor cells. Several recent clinical studies have suggested that the cell cycle kinetics of human tumors can likewise be altered by exog enous nutrient administration. This review will emphasize both laboratory and clinical studies which analyze the effect of nutrition support on tumorigenesis, tumor cell cycle kinetics, primary tumor growth, and tumor metastasis.
