Risk of metachronous recurrence after endoscopic submucosal dissection of esophageal squamous cell carcinoma.

Development of endoscopic submucosal dissection (ESD) improves the en bloc resection rate of superficial esophageal squamous cell carcinoma (SESCC). Although the background mucosa after ESD remains malignant potential, esophageal (sub)circumferential ESD, in cases where the mucosal defect is greater than three-fourths of the circumference, might induce refractory stricture, and it may disturb early detection of the recurrence. Therefore, we aimed to elucidate whether the patients treated by (sub)circumferential ESD for SESCC may remain at risk of metachronous recurrence. In a single-center retrospective study, we collected data from 154 consecutive patients who were treated with curative ESD for SESCC from 2002 to 2013 and followed by surveillance for longer than 12 months. Metachronous recurrence was defined as histologically proven SESCC at other site of the ESD scar or abnormal nodal swelling was detected later than 12 months after ESD. The primary endpoint was to identify the risk of metachronous recurrence using multivariate analyses. The secondary endpoint was to investigate difference in clinical pathological features between patients with and without the recurrence. The overall rate of metachronous recurrence was 14.9% during 40.5 median months after the initial ESD. 24.1% and 9.0% of overall metachronous recurrence were observed in patients treated with (sub)circumferential ESD and non-subcircumferential ESD, respectively, despite no significant difference in their observation duration. After the application of a stepwise regression model that included all variants, a Cox proportional hazards regression model identified (sub)circumferential ESD as the only risk for the recurrence (hazard ratio (HR): 1.48, 95% confidence intervals (CI): 1.04-2.08, P = 0.028). The cumulative recurrence rate revealed a significant difference between patients treated by (sub)circumferential ESD and those by nonsubcircumferential ESD (HR: 3.094, 95% CI: 1.33-7.52, P = 0.009), despite no significant difference in their cause-specific survival. Additionally, the session numbers of the follow-up endoscopy until the detection of metachronous recurrence after the non-subcircumferential ESD were significantly less than those after the (sub)circumferential ESD (7.8 ± 1.8 vs. 15.2 ± 1.5 P = 0. 005), despite no significant difference in their cancer-free duration. In conclusion, we demonstrated that patients treated by curative (sub)circumferential ESD for SESCC might be high risk for metachronous recurrence. Therefore, we should establish a risk-stratified surveillance program after (sub)circumferential ESD and preventive strategies for post-ESD stricture.