Characteristics of Primary and Metachronous Gastric Cancers Discovered after Helicobacter pylori Eradication: A Multicenter Propensity Score-Matched Study

Background/Aims Gastric cancers develop even after successful Helicobacter pylori eradication. We aimed to clarify the characteristics of early gastric cancers discovered after H. pylori eradication. Methods A total of 1,053 patients with early gastric cancer treated by endoscopic submucosal dissection were included. After matching the propensity score, we retrospectively investigated the clinicopathological features of 192 patients, including 96 patients who had undergone successful H. pylori eradication (Hp-eradicated group) and 96 patients who had active H. pylori infection (Hp-positive group). Results In the Hp-eradicated group, early gastric cancers were discovered 1 to 15 years (median, 4.1 years) after H. pylori eradication. Compared with Hp-positive patients, Hp-eradicated patients showed a more frequently depressed configuration (81% vs 53%, respectively, p<0.0001) and a higher trend toward submucosal invasion (18% vs 8%, respectively, p=0.051). A multivariable analysis revealed the macroscopic depressed type to be characteristics of early gastric cancers after H. pylori eradication. Among patients in the Hp-eradicated group, metachronous cancers showed less frequent depressed lesions (68% vs 84%, respectively, p=0.049) and smaller tumor sizes (median, 11 mm vs 14 mm, respectively, p=0.014) than primary cancers. Conclusions Early gastric cancers after H. pylori eradication are characterized by a depressed configuration. Careful follow-up endoscopies are necessary after H. pylori eradication.