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 18F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-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. (18)F-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 (18)F-FDG metabolic response after the neoadjuvant CRT and histopathological response. Presently, the contribution of (18)F-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.