Positive correlations between tumor uptake on FDG PET and energy expenditure of patients with esophageal cancer

Purpose Cancer patients are prone to clinical malnutrition; moreover, the energy expenditure in patients with certain cancers is higher than that in healthy individuals, rendering their nutritional management a challenging issue. We hypothesized that 2-deoxy-2-[¹⁸F]fluoro-D-glucose (FDG) uptake on positron emission tomography (PET) may be related to the energy expenditure and analyzed the FDG uptake and energy expenditure in esophageal cancer patients to clarify this. Methods Esophageal cancer patients [n = 13, 10 males and 3 females, age 66.5 ± 8.9 (51-82) years] were evaluated for FDG uptake using PET. The resting energy expenditure (REE) and basal energy expenditure (BEE) were calculated using indirect calorimetry and the Harris- Benedict formula, respectively. Regression analyses were performed to compare the parameters of imaging and energy expenditure. Results Positive correlations were found between tumor uptake on FDG PET and the parameters of energy expenditure. Among them, the correlations between SUV_max and the ratio of REE to BEE (REE/BEE, r = 0.59; p = 0.035) and between SUV_max and the difference between REE and BEE (REE - BEE, r = 0.58; p = 0.036) were moderate and statistically significant. Further, the correlation between tumor uptake expressed as a percentage (%TU) and REE/BEE was mild (r = 0.51) but not significant (p = 0.07), while that between %TU and REE-BEE was weak (r = 0.42) and not significant (p = 0.15). Conclusion Significant positive correlations between SUV_max on FDG PET and energy expenditure were noted in our study; we consider that these results may aid in determining the nutritional management for esophagealcancer patients.