Incidence of Metachronous Remnant Gastric Cancer after Proximal Gastrectomy with the Double-flap Technique (rD-FLAP-rGC Study): A Multicenter, Retrospective Study

Background: Although proximal gastrectomy (PG) with the double-flap technique (DFT) is a function-preserving surgery that prevents esophagogastric reflux, there is a risk of developing metachronous remnant gastric cancer (MRGC). Moreover, details of MRGC and appropriate postoperative follow-up after PG with DFT are unclear. Methods: We reviewed the medical records of 471 patients who underwent PG with DFT for cancer in a preceding, multicenter, retrospective study (rD-FLAP Study). We investigated the incidence of MRGC, frequency of follow-up endoscopy, and eradication of Helicobacter pylori (H. pylori) infection. Results: MRGC was diagnosed in 42 (8.9%) of the 471 patients, and 56 lesions of MRGC were observed. The cumulative 5- and 10-year incidence rates were 5.7 and 11.4%, respectively. There was no clinicopathological difference at the time of primary PG between patients with and without MRGC. Curative resection for MRGC was performed for 49 (88%) lesions. All patients with a 1-year, follow-up, endoscopy interval were diagnosed with early-stage MRGC, and none of them died due to MRGC. Overall and disease-specific survival rates did not significantly differ between patients with and without MRGC. The incidence rate of MRGC in the eradicated group after PG was 10.8% and that in the uneradicated group was 19.6%, which was significantly higher than that in patients without H. pylori infection at primary PG (7.6%) (p = 0.049). Conclusions: The incidence rate of MRGC after PG with DFT was 8.9%. Early detection of MRGC with annual endoscopy provides survival benefits. Eradicating H. pylori infection can reduce the incidence of MRGC.