Long-term surveillance and treatment outcomes of metachronous gastric cancer occurring after curative endoscopic submucosal dissection

Background and study aims: As more early gastric cancer (EGC) patients are being treated with endoscopic submucosal dissection (ESD), it is important to understand the outcomes of patients who develop metachronous gastric cancer (MGC). The aim of this study was to evaluate the long-term surveillance and treatment outcomes of MGC after curative gastric ESD. Patients and methods: The study included 1526 consecutive patients who underwent curative ESD resection of EGC. They were generally followed by annual or biannual esophagogastroduo-denoscopy. The risk factors and treatment outcomes for MGC were assessed along with the 5-year, 7-year, and 10-year cumulative incidence functions of MGC and disease-specific survival (DSS). Results: During a median follow-up period of 82.2 months, 238 patients developed MGC post-ESD resection of EGC. The 5-year, 7-year, and 10-year cumulative incidence functions of MGC were 9.5 %, 13.1% and 22.7 %, respectively. Male sex and multiple initial EGCs were independent risk factors for MGC in the Cox proportional hazard model. Of the 238 patients with MGC, 215 were treated with endoscopic resection, of which 183 achieved curative resection, although one patient later died of his initial EGC. A further 14 patients were treated surgically, three had metastatic disease and received palliative chemotherapy, and the remaining six were observed without any intervention. A total of seven patients died of MGC, five at least 5 years after their index ESD. The 5-year, 7-year, and 10-year DSSs were 99.2 %, 98.6 %, and 92.5 %, respectively. Conclusions: The incidence of MGC increases with time after curative gastric ESD, therefore surveillance endoscopy should be continued indefinitely.