title: Helicobacter pylori-negative gastric cancer in South Korea: incidence and clinicopathologic characteristics.
abstract: OBJECTIVE
  It is difficult to determine the exact incidence rate of Helicobacter pylori (H. pylori) infection-negative gastric cancer (HPIN-GC) because H. pylori detection rates decrease with the progression of gastric atrophy and intestinal metaplasia. The aim of this study was to evaluate the incidence and clinicopathologic characteristics of HPIN-GC in South Korea.
  
  
  METHODS
  Helicobacter pylori infection status was evaluated by histology, a rapid urease test (CLO test), culturing, serology, and history of H. pylori eradication for 627 patients with gastric cancer. Current H. pylori infection was defined as positive results from histology, the CLO test, and culturing. Previous H. pylori infection was defined as negative in all three biopsy-based tests and positive serology or history of H. pylori eradication. Patients were considered to be negative for H. pylori infection if all results from five methods were negative. However, patients who were found to have severe gastric atrophy by the serum pepsinogen test or metaplastic gastric atrophy by histology were assumed to have had a previous H. pylori infection even if results from other tests for H. pylori infection were all negative.
  
  
  RESULTS
  The number of patients with gastric cancer with current or previous H. pylori infection was 439 (70.0%) and 154 (24.6%), respectively. The rate of HPIN-GC occurrence was 5.4% (n = 34). Sex, age, Lauren type, location of the tumor, and treatment modalities were not different according to H. pylori infection status. However, HPIN-GC had a more advanced pT classification (T3/T4; 51.9 vs 31.1%, p = .025) and a more advanced stage (more than stage I; 63 vs 41.3%, p = .027) than H. pylori-positive gastric cancer.
  
  
  CONCLUSIONS
  At least 5.4% cases of gastric cancer were H. pylori negative among South Korean patients. HPIN-GC looks like to have a poorer prognosis than H. pylori-positive cases.
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Yoon
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Lee
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Shin
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Park
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
authors.forename: Hyun Chae
authors.initials: HC
authors.lastname: Jung
authors.forename: In Sung
authors.initials: IS
authors.lastname: Song
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D016481:Helicobacter Infections / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D016480:Helicobacter pylori; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology