Prognosis Prediction by <sup>18</sup>F-fluorodeoxyglucose Positron Emission Tomography Parameters in Patients Undergoing Chemoradiation Therapy for Esophageal Cancer

The aim of this study was to identify ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) parameters that could predict the prognosis of patients with esophageal cancer before and after undergoing chemoradiation therapy. We retrospectively reconstructed images under the same conditions for patients who underwent pre- and post-treatment ¹⁸F-FDG-PET for chemoradiation therapy for esophageal cancer. Correlations between 2-year survival rates and pre-treatment values, differences between pre- and post-treatment quotients, and their ratios were examined for various standardized uptake values (SUV), metabolic tumor volumes (MTV), and each SUVmean (Mean SUV)*MTV (Vol.mean). We enrolled 29 patients who underwent pre-and post-treatment ¹⁸F-FDG-PET. The median overall survival was 21.4 months (range, 3.6-100.9 months). Pre-treatment MTV had the most favorable hazard ratio (HR) for survival. However, the MTV product (Vol.meanQ), SUV corrected for basal metabolic rate using Mifflin-St Jeor estimation (BMR.ms), Vol.mean (SUVmeanQ) using the qPET method, SUVmean, and HR using Vol.meanQ corrected for body weight were nearly equivalent. No significant results were obtained for the pre- and post-treatment quotients. The pre- and post-treatment Vol.meanQ is a useful prognostic parameter that considers the effect of age-related loss of lean body mass. The use of parameters, including metabolism, will facilitate more appropriate use of ¹⁸F-FDG-PET before and after chemoradiation therapy.