BackgroundNeoadjuvant chemoradiotherapy (NCRT) has shown promise in improving the prognosis of individuals with locally advanced esophageal squamous cell carcinoma (LA-ESCC). However, the factors influencing tumor response and long-term survival in these patients remain unknown. The optimal timing for surgery after the completion of radiotherapy in LA-ESCC remains controversial. Therefore, this study was designed to identify biomarkers and to determine the optimal post-NCRT time-to-surgery (TTS) for patients with LA-ESCC.MethodsThis retrospective study included patients with resectable LA-ESCC who underwent NCRT between May 2017 and June 2021. The tumor shrinkage rate was calculated as the difference between the pre- and post-primary gross tumor volume (GTVp) divided by the pre-GTVp. Univariate and multivariate Cox regression analyses and Kaplan-Meier curves were used to calculate overall survival (OS) and progression-free survival (PFS).ResultsWe collected data from 248 patients with resectable LA-ESCC who underwent computed tomography (CT) scans before the initiation of treatment. The median follow-up time was 37.7 months. The optimal cutoff of tumor shrinkage was 45%. In the univariate and multivariate analyses, we found a significant association between the tumor shrinkage rate and PFS (p = 0.001). Among the subgroup of patients who responded to treatment, extending the TTS was associated with improved OS (p = 0.037) and PFS (p = 0.028).ConclusionsFor patients with resectable LA-ESCC, the tumor shrinkage rate is an independent prognostic factor for PFS. Thus, for responders, prolonging TTS is recommended to obtain a better OS.