Body composition in malignant disease.

It has been suggested that adaptation to starvation may be impaired in patients with malignant disease and that this may contribute to the development of cancer cachexia. We have investigated this by comparing the body composition, as well as the tissue composition of weight loss, of a group of 49 patients with gastrointestinal carcinomas and 91 patients with benign gastrointestinal disease all of whom had sustained a weight loss greater than 10% of their recalled pre-illness weight. Total body protein was calculated from total body nitrogen measured by in vivo neutron activation analysis which also provided absolute values of sodium, chlorine, phosphorus, and calcium. The masses of muscle and nonmuscle protein were estimated using a validated compartmental analysis. Total body fat was derived using anthropometry. Total body water was estimated from the difference between body weight and the sum of body protein, fat, and minerals. The loss of body weight incurred by patients with both benign and malignant disease was primarily muscle mass and body fat. Both groups of patients retained nonmuscle protein. All patients manifested, with increasing weight loss, a progressive loss of muscle protein, fat, and water, which must represent the tissue composition of weight loss. No significant differences between patients with benign or malignant disease were demonstrated for any of the body composition parameters measured. The results of this study do not support the hypothesis that adaptation to starvation in patients with cancer is in anyway different from that which occurs in patients with benign disease.