ABSTRACT. Controversy exists regarding the use of nutrition support in the cancer patient. Although nutrition support can clearly improve host nutritional status and restore immunoconfidence, the efficacy of nutrition support to reduce morbidity and mortality associated with antineo-plastic therapy is questionable. A potential concern with the use of nutrition support in the tumor - bearing host is stimulation of primary tumor growth and metastasis. Numerous animal studies clearly demonstrate that oral and parenteral nutrition can significantly stimulate tumor cell proliferation and distant metastasis. Although cellular kinetic studies in humans have shown alterations after parenteral nutrition, objective measures of tumor growth. Metastasis and tumor protein synthesis has not been affected by parenteral nutrition. This chapter summarizes the research and clinical work regarding the effect of nutrients on tumorigenesis, primary tumor growth, and metastasis in both animal and human tumors. (Journal of Parenteral and Enteral Nutrition 16:72S- 75S)
The effect of nutrition support in the cancer patient remains controversial. Although extensive nutritional and metabolic alterations have been demonstrated in the cancer patient, a potential concern with the use of nutrition support in this patient population is stimulation of tumor growth. Previous studies clearly have demonstrated an increased incidence of spontaneous tumor development in animal models associated with increased caloric and fat diets. In contrast, protein- calorie deprivation causes a reduction in spontaneous tumorigenesis and a decreased rate of establishment of transplanted tumors. Furthermore, numerous animal studies have shown acceleration of tumor growth and tumor metastasis occurs during periods of nutritional repletion. The relative benefits of nutrition support in the cancer patient regarding host survival are inconclusive.
Clinical studies similarly have been controversial regarding the efficacy of nutrition support to reduce morbidity and mortality associated with surgery, chermotherapy, or radiation therapy in the cancer patient. Significantly reduced complications can only be demonstrated in severely malnourished cancer patients. However, inadequate numbers of patients, inappropriate patient populations, suboptimal levels of nutrition support, and heterogeneity of patient populations flaw the majority of these studies. Nevertheless, the relative risks and benefits of the use of nutrition support in the cancer patient have not been clearly defined. This review will locus on both laboratory and clinical studies that examine the effect of nutrition support on tumor development, primary tumor growth, and tumor metastasis.
TUMORIGENESIS AND TUMOR ESTABLISHMENT
Previous animal studies have demonstrated that protein-calorie restriction can significantly reduce the incidence of spontaneous tumorigenesis. In addition, tumor establishment and growth rates of transplanted tumors are significantly decreased under conditions of protein-calorie restriction. Tannenbaum and Silverstone in 1953 published an extensive review demonstrating that protein and/or calorie deprivation significantly inhibited spontaneous tumorigenesis in numerous tumor systems in mouse and rat models. Green et al in 1950 documented delayed establishment of
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