Does higher radiation dose lead to better outcome for non-operated localized esophageal squamous cell carcinoma patients who received concurrent chemoradiotherapy? A population based propensity-score matched analysis

Background: The optimal radiotherapy dose for non-operated localized esophageal squamous cell carcinoma (NOL-ESCC) patients undergoing concurrent chemoradiotherapy (CCRT) is hotly debated. Methods: We identified eligible patients diagnosed within 2008-2013 from Taiwan Cancer Registry and constructed a propensity score matched cohort (1:1 for high dose (>= 60 Gy) vs standard dose (50-50.4 Gy)) to balance observable potential confounders. We compared the hazard ratio (HR) of death between standard and high radiotherapy dose groups during the entire follow-up period. We performed sensitivity analysis (SA) to evaluate the robustness of our finding regarding potential unobserved confounders & index date definition. Results: Our study population constituted 648 patients with well balance in observed co-variables. The HR of death when high dose was compared to standard dose was 0.75 (95% confidence interval 0.64-0.88). Our result was sensitive to potential unobserved confounders but robust to alternative index date definition in SA. Conclusions: We found that higher than standard radiotherapy dose may lead to better survival for NOL-ESCC patients undergoing CCRT. (C) 2016 Elsevier Ireland Ltd. All rights reserved.