Comparative effectiveness of image-guided radiotherapy for non-operated localized esophageal squamous cell carcinoma patients receiving concurrent chemoradiotherapy: A population-based propensity score matched analysis

BACKGROUND Although concurrent chemoradiotherapy (CCRT) coupled with image-guided radiotherapy (IGRT) is associated with a theoretical benefit in non-operated localized esophageal squamous cell carcinoma (NOL-ESCC) patients, there is currently no clinical evidence to support this. RESULTS The study population in the primary analysis comprised 866 patients who were well balanced in terms of their co-variables. The HR for mortality when group A was compared with group B was 0.82 (95% confidence interval, 0.7-0.95). SA revealed that the result was moderately sensitive. MATERIALS AND METHODS Eligible patients diagnosed between 2008 and 2013 were identified in the Taiwan Cancer Registry. A propensity score-matched cohort was constructed [1:1 in groups A (with IGRT) and B (without IGRT)] to balance any observable potential confounders. The hazard ratio (HR) for mortality was compared between groups A and B during the follow-up period. Sensitivity analyses (SA) were performed to evaluate the robustness of the findings regarding the selection of confounders and a potential unobserved confounder. CONCLUSIONS The current results provide the first clinical evidence that CCRT coupled with IGRT is associated with better overall survival when compared with CCRT without IGRT in NOL-ESCC patients. However, this study should be interpreted with caution given its non-randomized nature and the moderate sensitivity of the data. Further studies are needed to clarify this finding.