Objective: Increased resting energy expenditure (REE) is thought to confer a poor prognosis in patients with non-small cell lung cancer (NSCLC). However, no study has validated this hypothesis to date. This study's objective was to examine the prognostic significance of REE in NSCLC.
Methods: Seventeen patients with NSCLC (stages IA-IIIB) underwent measurement of REE with indirect calorimetry before the initiation of cancer treatment. Similar measurements were performed in 17 control subjects, each of whom was matched to a cancer patient by age ( +/-5 years), sex and body mass index ( +/-3 kg/m2). Patients were classified as hypermetabolic or hypometabolic based on a direct comparison of measured REE between cancer patients and their matched controls. After cancer treatment, these 17 patients were followed for evidence of metastatic disease for up to 32 months.
Results: Six patients developed metastatic disease. The eight hypometabolic cancer patients had a significantly shorter mean disease-free survival compared to the nine hypermetabolic cancer patients: 19 months (95% confidence interval (CI) 12, 26) versus 29 months (95% CI 24, 34), respectively (P < 0.05 by log-rank test). In contrast, Cox regression showed no relationship between disease-free survival and differences in REE between cancer patients and their matched controls (P = 0.20).
Conclusions: These results suggest that hypermetabolism may predict a longer disease-free survival in NSCLC patients. This finding differs from the prevailing hypothesis that hypometabolic patients with NSCLC survive longer, and deserves further investigation.