The effects on resting energy expenditure of different tumor types.

The presence of a malignant tumor is said to influence the resting energy expenditure (REE) of the host. This study assesses the hypothesis that different tumor types exert differing effects on REE. REE was measured using indirect calorimetry in 84 cancer patients. Fifty-one patients had colorectal cancer, 22 had gastric cancer, and 11 had non-small cell bronchial cancer. For each tumor type, REE correlated significantly with body weight and lean body mass (LBM). The slope of the regression line for the bronchial cancer patients was significantly different from the colorectal (P less than 0.02) and gastric (P less than 0.02) cancer patients when REE was related to LBM. When related to body weight, the slope of the line of the bronchial cancer patients was significantly different from that of the gastric cancer patients only (P less than 0.05). The bronchial cancer patients had a significantly higher REE than the colorectal (P less than 0.005) and gastric (P less than 0.02) cancer patients when REE was expressed in terms of body weight. However, when corrected for LBM, no significant differences in REE were found between the groups. The presence of hepatic metastases did not influence REE in any of the tumor groups. Differing relationships between REE and indices of body size have been detected in differing tumor types. Consequently, the use of heterogeneous cancer groups may be inappropriate in studies of REE and cancer.