Prognostic analysis of remarkable response after radiotherapy or chemoradiotherapy in esophageal cancer

Standardized criteria for endoscopic assessment of the treatment response of esophageal squamous cell carcinoma (ESCC) are limited. The Japan Esophageal Society recently proposed the remarkable response, which is defined as marked tumor reduction with residual disease but an invasion depth equivalent to T1. However, its prognostic value has not yet been established. We aimed to evaluate whether remarkable response predicts survival outcomes of patients with esophageal squamous cell carcinoma. In this retrospective single-center study, we analyzed 300 consecutive patients with ESCC who underwent radiotherapy or chemoradiotherapy between March 2014 and March 2025. Patients were categorized into the complete response, remarkable response, or nonremarkable response group. The primary endpoint was overall survival. Survival outcomes were assessed using the Kaplan-Meier analysis and Cox proportional hazards models. The complete response, remarkable response, and nonremarkable response groups comprised 99, 116, and 85 patients, respectively. Overall survival (OS) was significantly better in the remarkable response group than in the nonremarkable response group. Outcomes of the remarkable response group were comparable to those of the complete response group. The 5-year OS rates were 79.4%, 61.0%, and 25.5% in the complete response, remarkable response, and nonremarkable response groups, respectively. In the multivariate analysis, the endoscopic response was an independent prognostic factor, and remarkable response was associated with a significantly reduced risk of death compared with that associated with nonremarkable response. Incorporation of remarkable response in the posttreatment endoscopic evaluation may support prognostic estimation and inform subsequent management.