Prognostic Significance of Stratification Using Pathological Stage and Response to Neoadjuvant Chemotherapy for Esophageal Squamous Cell Carcinoma.

Abstract

PURPOSE: Risk stratification to select appropriate candidates for adjuvant therapy is required for esophageal cancer patients based on adjuvant therapy advancement including immunotherapy. The current study aims to develop a novel staging system using pathological stage (pStage) and response to neoadjuvant chemotherapy (NAC) for esophageal squamous cell carcinoma (ESCC). METHODS: ESCC patients who received NAC and underwent transthoracic esophagectomy at two Japanese high-volume esophageal centers were retrospectively reviewed. The prognostic value of NAC response was evaluated within the same pStage, and a novel risk stratification to predict cancer-specific survival (CSS) was developed. RESULTS: The HR (95% CI) of pathological responders in pStage 0-I, II, III, and IV was 0.29 (0.07-1.17), 0.37 (0.12-1.10), 0.37 (0.15-0.92), and 0.24 (0.06-0.98), respectively. Responders in pStage 0-II were classified to be in the same class and those in pStage III/IV in another group, because the 5-year CSS (5y-CSS) rate of responders in pStage 0-I, II, III, and IV was 94%, 92%, 76%, and 71%, respectively. Combining nonresponders in pStage 0-II as the same group, all patients were subdivided into five groups. Intriguingly, the 5y-CSS in pStage III-IV responders was 75%, almost identical to that of nonresponders in pStage 0-II (78%). CONCLUSIONS: The histological response influenced the long-term outcomes of patients who underwent esophagectomy after NAC, even within groups stratified by pathologic stage. The current risk stratification system will contribute to selecting appropriate candidates for adjuvant therapy.