Salvage endoscopic resection (ER) after chemoradiotherapy for esophageal squamous cell carcinoma: What are the risk factors for recurrence after salvage ER?

Background and Aim: Salvage endoscopic resection (ER) is among the curative treatments for superficial local failure after chemoradiotherapy (CRT) for esophageal squamous cell carcinoma (ESCC). The present study aimed to clarify risk factors for recurrence after salvage ER. Methods: This study enrolled consecutive ESCC patients treated with salvage ER for local failure after CRT between 1998 and 2013. Recurrences after salvage ER included locoregional recurrences and distant metastases. Multivariate analysis was carried out on clinicopathological parameters to identify risk factors for post-salvage ER recurrence. Results: Of the 72 patients enrolled in this study, 37/8/23/4 patients had been staged before CRT as cT1/T2/T3/T4 and 44/28 patients as cN0/N1, respectively, and local failures detected before salvage ER were residual lesions after CRT in 19 and local recurrences in 53 patients. Resected specimens were classified as pT1a (M) in 45 and pT1b (SM) in 27 patients. During the median 45-month follow up (range, 3-175 months) after salvage ER, 27 (38%) patients developed recurrence with a 3year recurrence-free survival rate of 48.9% (95% confidence interval [CI], 36.5-60.3). Multivariate analysis showed that residual lesions after CRT (HR, 2.55; 95% CI, 1.32-4.94) and lesions with a submucosal tumor (SMT)-like appearance before salvage ER (HR, 2.08; 95% CI, 1.04-4.18) were significantly associated with post-salvage ER recurrence. Conclusions: Clinical findings (e.g. residual tumors found immediately after CRT and macroscopic SMT-like appearance before salvage ER) were shown to be significant risk factors for post-salvage ER recurrence.