Survival benefit of additional surgery after noncurative endoscopic resection in patients with early gastric cancer

Background and Aims: Excellent long-term outcome is expected for early gastric cancers (EGCs) after endoscopic submucosal dissection (ESD). However, if ESD is considered noncurative at the pathologic evaluation, additional surgery is recommended. We evaluated whether long-term outcome is compromised if additional surgery is not performed for EGCs that are out-of-indication. Methods: We retrospectively analyzed a cohort of patients with EGC not meeting ESD indications whose initial treatment was either ESD (n = 219) or surgery (n = 1799). Among them, 127 patients who underwent additional surgery after initial ESD and 67 patients who did not were matched using propensity scores to patients who initially underwent standard surgery, at a 1:1 ratio. Overall mortality and gastric cancer recurrence were compared. Results: The overall mortality and gastric cancer recurrence rates were not significantly different between the 127 patients who underwent initial ESD with additional surgery and the corresponding initial standard surgery patients. However, the overall mortality of the 67 patients who underwent ESD without additional surgery (5-year mortality, 26.0%; 95% CI, 13.5%-49.9%) was higher than that of the matched initial standard surgery patients (5-year mortality, 14.5%; 95% CI, 6.3%-33.6%; P = .04). Gastric cancer recurrence was also higher in ESD patients without additional surgery (5-year recurrence, 17.0%; 95% CI, 7.6%-37.8%) than in the matched initial surgery group (0%; P = .002). In multivariate analyses, ESD without additional surgery was a significant risk factor for overall mortality and gastric cancer recurrence. Conclusions: Additional surgery should be encouraged after non-curative ESD to obtain long-term outcomes comparable with those of initial standard surgery. (Clinical trial registration number: NCC2015-0093.)