Cancer cachexia and protein metabolism.

Metabolic abnormalities arising from malnutrition and malignancy are seen in patients with cancer cachexia. To discriminate between the effects of pure malnutrition and tumour-specific metabolic alterations, the kinetics of whole-body metabolism were determined in 7 untreated, malnourished cancer patients and in 11 patients with benign disease, also malnourished, by means of primed constant infusion of 15N-glycine. Patients in both groups received 500 kcal/day as 5% glucose solution without any nitrogen. Whole-body protein turnover was 32% and 35% higher in the cancer patients than in the non-cancer patients and starved normal subjects respectively. Similarly, the rate of protein synthesis was 35% and 54% higher in the cancer patients than in the non-cancer patients and starved normal subjects respectively. Our study supports the view that aberrations of host metabolism in patients with cancer cachexia are different from those in non-cancer patients suffering equivalent weight loss.