Prognostic value of metabolic response measured by 18F-FDG-PET in oesophageal cancer patients treated with definitive chemoradiotherapy

BackgroundThis study aimed to assess the efficacy of fluorine-18 fluorodeoxyglucose (F-18-FDG)-PET for predicting overall survival (OS) and disease-free survival (DFS) in oesophageal cancer patients after definitive chemoradiotherapy (CRT) and prognostic importance of metabolic response detected by post-treatment PET at least 3 months after completing CRT.Materials and methodsData from 58 oesophageal cancer patients receiving definitive CRT were retrospectively analysed. Post-treatment F-18-FDG-PET was delivered at a median of 3.2 (range, 3.0-6.4) months after CRT. The impact of metabolic response determined by post-treatment F-18-FDG-PET, maximum post-treatment standardized uptake value (SUVmax) and percent SUV change (pretreatment to post-treatment) on survival was analysed.ResultsThe median follow-up was 19.7 (range, 4.2-91.9) months for all patients and 28.2 (range, 13.7-91.9) months for survivors. The mean pretreatment and post-treatment SUVmax and the median percent SUV decrease were 18.66.4, 6.2 +/- 4.6 and -73% (+13 to -100%). Pretreatment SUVmax was higher in patients with locoregional or distant failure than in those without (P<0.001). Pretreatment SUVmax was lower in patients with a complete response (CR) than in those without a CR (P=0.006). Two-year OS and DFS were higher in patients with CR compared with those without CR (P<0.001). CR rates detected by post-treatment F-18-FDG-PET were lower in patients with lymph node metastases or longer tumours than in those with shorter tumours or no metastases. During multivariate analysis, post-treatment SUVmax was a significant predictor for OS, and post-treatment SUVmax, percent SUV decrease and tumour length were significant prognostic factors for DFS.ConclusionMetabolic response assessed by post-treatment F-18-FDG-PET at least 3 months after CRT showed that post-treatment SUVmax and percent SUV change were important survival predictors.