Energy Expenditure in Malnourished Cancer Patients

Abstract

The presence of a malignancy may cause increased energy expenditure in the cancer patient. To test this hypothesis, resting energy expenditure (REE) were measured by bedside indirect calorimetry in 200 heterogeneous hospitalized cancer patients. Measured resting energy expenditure (REE-M) was compared with expected energy expenditure (REE-P) as defined by the Harris-Benedict formula. The study population consisted of 77 males and 123 females with a variety of tumor types: 44% with gastrointestinal malignancy, 29% with gynecologic malignancy and 19% with a malignancy of genitourinary origin. Patients were classified as hypometabolic (REE < 90% of predicted), normometabolic (90-110% of predicted) or hypermetabolic (> 110% of predicted). Of patients 59% exhibited aberrant energy expenditure outside the normal range; 33% were hypometabolic (79.2% REE-P) 41% were normometabolic (99.5% REE-P) and 26% were hypermetabolic (121.9% REE-P) (P < 0.001). Aberrations in REE were not due to age, height, weight, sex, nutritional status (% weight loss, visceral protein status), tumor burden (no gross tumor, local or disseminated disease), or presence of liver metastasis. Hypermetabolic patients had significantly longer duration of disease (P < 0.04) than normometabolic patients (32.8 vs. 12.8 mo.), indicating that the duration of a malignancy may have a major impact upon energy metabolism. Cancer patients exhibit major aberrations in energy metabolism, but are not uniformly hypermetabolic. Energy expenditure cannot be accurately predicted in cancer patients using standard predictive formulae.