Energy expenditure in malnourished cancer patients

It is widely believed that the presence of a malignancy causes increased energy expenditure in the cancer patient. To test this hypothesis, resting energy expenditure (REE) was 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 less than 90% of predicted), normometabolic (90-110% of predicted) or hypermetabolic (greater than 110% of predicted). Fifty-nine per cent of patients exhibited aberrant energy expenditure outside the normal range. Thirty-three per cent were hypometabolic (79.2% REE-P), 41% were normometabolic (99.5% REE-P), and 26% were hypermetabolic (121.9% REE-P) (p less than 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 less than 0.04) than normometabolic patients (32.8 vs. 12.8 months), 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.