title: Incidence of gastric cancer among patients with gastric precancerous lesions: observational cohort study in a low risk Western population.
abstract: OBJECTIVE
  To accurately measure the incidence of gastric cancer among patients with gastric precancerous lesions, and to quantify the excess incidence in comparison with people with normal mucosa on endoscopy and a general population.
  
  
  METHODS
  Population based cohort study.
  
  
  METHODS
  Population of Sweden using data from its national disease registers.
  
  
  METHODS
  405,172 patients who had gastric biopsy samples taken for non-malignant indications between 1979 and 2011.
  
  
  METHODS
  Incidence of gastric cancer, reported separately for patients with different mucosal changes in biopsy samples. Standardised incidence ratios provided estimation of the relative risk, using the general Swedish population as reference; and hazard ratios were derived from Cox regression modelling for internal comparisons with patients with normal gastric mucosa.
  
  
  RESULTS
  After excluding the first two years of follow-up, 1599 cases of gastric cancer were identified. The annual crude incidence of gastric cancer was 20 × 10(-5) for those in the normal mucosa group (standardised incidence ratio 1.0), 42 × 10(-5) for those with minor changes (1.5), 59 × 10(-5) for the gastritis group (1.8), 100 × 10(-5) for the atrophic gastritis group (2.8), 129 × 10(-5) for the intestinal metaplasia group (3.4), and 263 × 10(-5) for the dysplasia group (6.5). Cox regression modelling confirmed that excess risks increased monotonically with progressive severity of gastric lesions, with the highest hazard ratio of 10.9 (dysplasia versus normal mucosa, 95% confidence interval 7.7 to 15.4). The increased incidence was stable throughout the follow-up period, and the gaps between cumulative incidence curves grew continuously.
  
  
  CONCLUSIONS
  Among patients who undergo gastroscopy with biopsy for clinical indications, approximately 1 in 256 with normal mucosa, 1 in 85 with gastritis, 1 in 50 with atrophic gastritis, 1 in 39 with intestinal metaplasia, and 1 in 19 with dysplasia will develop gastric cancer within 20 years. These numbers, along with cost-benefit analyses, should guide future surveillance policies for these particular patient groups.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden.
authors.forename: Huan
authors.initials: H
authors.lastname: Song
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden.
authors.forename: Isabella Guncha
authors.initials: IG
authors.lastname: Ekheden
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden.
authors.forename: Zongli
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Department of Pathology, Karolinska Hospital, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Ericsson
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden.
authors.forename: Olof
authors.initials: O
authors.lastname: Nyrén
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden weimin.ye@ki.se.
authors.forename: Weimin
authors.initials: W
authors.lastname: Ye
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D005260:Female; D005500:Follow-Up Studies; D005753:Gastric Mucosa / Q000473:pathology*; D005773:Gastroscopy; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000473:pathology*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012306:Risk; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000473:pathology*; D013548:Sweden / Q000453:epidemiology