Gastric cancer treated by endoscopic submucosal dissection or endoscopic mucosal resection in Japan from 2004 through 2006: JGCA nationwide registry conducted in 2013.

Background: The Japanese Gastric Cancer Association (JGCA) initiated a new nationwide gastric cancer registry in 2008 and reported the treatment outcomes of patients with primary gastric cancer who underwent surgical therapy in 2001 and 2003. However, the outcomes of endoscopic therapy have not been reported yet.

Methods: The JGCA conducted a retrospective nationwide registry in 2013 to investigate the short-term and long-term outcomes of endoscopic mucosal resection or endoscopic submucosal dissection in patients with gastric cancer treated from January 2004 through December 2006. This registry used a computerized database with terminology in accordance with the JGCA classification (13th and 14th editions) and the Japanese Gastric Cancer Treatment Guidelines from 2010.

Results: Accurate data on 12,647 patients were collected from 126 participating hospitals and analyzed. The treatment procedure was endoscopic submucosal dissection in 81% of the patients and endoscopic mucosal resection in 19%. En bloc and R0 resections were achieved in 89% and 79% of the patients respectively. The total proportion of patients who underwent curative resection was 69.2%; 43.8% of patients underwent curative resection for absolute indication lesions, and 25.4% underwent curative resection for expanded indication lesions. Emergency surgery was performed to treat bleeding or perforation in very few patients (0.3% and 0.4% respectively). The 5-year follow-up rate after endoscopic resection was 70%. The 5-year overall survival rate was 91.6% in patients with absolute indications and 90.3% in patients with expanded indications after curative resection and 86.5% in patients who underwent noncurative resection. The 5-year disease-specific survival rates were 99.9%, 99.7%, and 98.7% in patients with absolute indications who underwent curative resection, patients with expanded indications who underwent curative resection, and patients who underwent noncurative resection respectively.

Conclusion: Endoscopic resection of gastric cancer resulted in favorable short-term and long-term outcomes nationwide in Japan. Further efforts to increase the follow-up rate are needed.