title: Incidence of and risk factors for metachronous gastric cancer after endoscopic resection and successful Helicobacter pylori eradication: results of a large-scale, multicenter cohort study in Japan.
abstract: BACKGROUND
  A previous multicenter prospective randomized study from Japan showed that Helicobacter pylori eradication reduced the development of metachronous gastric cancer (MGC) after endoscopic resection for early gastric cancer. MGC risk, however, is not eliminated; yet few studies have evaluated its long-term incidence and risk factors. In this study, we investigated the incidence of and risk factors for MGC in patients who underwent endoscopic resection for early gastric cancer with successful H. pylori eradication.
  
  
  METHODS
  A total of 594 patients who underwent endoscopic resection for early gastric cancer and successful H. pylori eradication at three institutions (National Cancer Center Hospital, University of Tokyo Hospital, and Wakayama Medical University Hospital) were analyzed retrospectively. Annual endoscopic surveillance was performed after initial endoscopic resection. MGC was defined as a gastric cancer newly detected at least 1 year after successful H. pylori eradication.
  
  
  RESULTS
  Ninety-four MGCs were detected in 79 patients during the 4.5-year median follow-up period. Kaplan-Meier analysis showed the cumulative incidence of MGC 5 years after successful H. pylori eradication was 15.0 %; the incidence of MGC calculated by use of the person-year method was 29.9 cases per 1000 person-years. Multivariate analysis using the Cox proportional hazards model revealed that male sex, severe gastric mucosal atrophy, and multiple gastric cancers before successful H. pylori eradication were independent risk factors for MGC. Eleven percent of MGCs (10 of 94) were detected more than 5 years after successful H. pylori eradication.
  
  
  CONCLUSIONS
  Surveillance endoscopy for MGC in patients who have undergone endoscopic resection for early gastric cancer should be performed even after successful H. pylori eradication.
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Genki
authors.initials: G
authors.lastname: Mori
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan. tnakajim@ncc.go.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakajima
authors.affiliation: Division of Epigenomics, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Asada
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Shimazu
authors.affiliation: Department of Gastroenterology, University of Tokyo, Tokyo, Japan.
authors.forename: Nobutake
authors.initials: N
authors.lastname: Yamamichi
authors.affiliation: Second Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Maekita
authors.affiliation: Department of Gastroenterology and Hepatology, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Chizu
authors.initials: C
authors.lastname: Yokoi
authors.affiliation: Department of Gastroenterology, University of Tokyo, Tokyo, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Fujishiro
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Gotoda
authors.affiliation: Second Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Ichinose
authors.affiliation: Division of Epigenomics, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Ushijima
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Oda
mesh_terms: D000328:Adult; D000368:Aged; D004724:Endoscopy; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy / Q000009:adverse effects*; D005773:Gastroscopy; D016481:Helicobacter Infections / Q000150:complications* / Q000821:virology; D016480:Helicobacter pylori; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016609:Neoplasms, Second Primary / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology / Q000601:surgery; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology / Q000601:surgery; D015996:Survival Rate
keywords: Gastric cancer; Helicobacter pylori; Incidence; Multivariate analysis; Risk factors