The relationship between resting energy expenditure and weight loss in benign and malignant disease.

The relationship between cancer, weight loss, and resting energy expenditure (REE) has been investigated in 136 patients using indirect calorimetry. Ninety-one patients had gastric, colorectal, or nonsmall cell bronchial neoplasm, seven patients had other malignancies, and 38 patients had nonmalignant illness. Four groups were studied: weight stable cancer patients (CWS: N = 56), weight losing cancer patients (CWL: N = 42), weight stable patients with nonmalignant illness (NCWS: N = 22), and weight losing patients with nonmalignant illness (NCWL: N = 16). In each group REE correlated significantly with body weight, metabolic body size, and lean body mass (LBM: estimated from total body water measurements). The closest correlation was between REE and lean body mass, with the slope of the CWL regression line differing significantly from that of the CWS (p less than 0.05) and NCWS (p less than 0.02) groups. However, there was no difference in REE expressed as kcal/kg LBM/d between the groups. The slopes of the regressions between REE and LBM were almost identical when all cancer patients were compared with all patients with nonmalignant illness. However, when all weight stable patients were compared with all weight losing patients, there was a highly significant difference between the slopes of the regressions (p less than 0.005). This indicates that the weight losing state rather than the presence or absence of cancer is responsible for an alteration in the relationship between REE and LBM. There were no differences in REE between the different tumor types. It is concluded that REE is not elevated in patients with gastric, colorectal, or nonsmall cell bronchial cancer. Elevation of REE contributes very little to the etiology of cancer cachexia.