The value of 18F-FDG PET/CT in assessment of metabolic response in esophageal cancer for prediction of histopathological response and survival after preoperative chemoradiotherapy

Aim. To evaluate the ability of hybrid F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/CT) to predict histopathological response and overall survival (OS) after preoperative neoadjuvant chemoradiotherapy (CRT) in patients with the esophageal carcinoma. Methods. 73 patients with locally advanced esophageal carcinoma were included in the study. All were treated with CRT and 34 subsequently underwent surgical resection of the esophagus. F-18-FDG PET/CT was carried out prior to (PET/CT1) and 6 weeks after (PET/CT2) completion of the CRT. Results. PET/CT2-determined complete metabolic response (CMR) was achieved in 6 (17.6%) out of 34 operated patients, the metabolic response was incomplete (NCMR) in 28 (82.4%) patients. A histopathological complete response (CR) to CRT was discovered in 7 patients (20.6%). The median OS in operated patients was 17.1 months, 95% CI: 12.9-23.3 months. In a group of 39 non-operated patients, CMR after neoadjuvant CRT was achieved in 12 patients (30.8%), while NCMR was found in 28 (82.4%). The median OS was 13.5 months in this group, 95% CI: 4.4-22.7 months. Conclusion. No statistically significant correlation was found between the F-18-FDG metabolic response after the neoadjuvant CRT and histopathological response. Presently, the contribution of F-18-FDG PET/CT as a marker of the potential result of CRT cannot be considered definite. Another study with a larger sample of patients and standardized algorithms for the examining protocols would be necessary for reaching definitive conclusions.