title: Optimal Interval for Repeated Gastric Cancer Screening in Normal-Risk Healthy Korean Adults: A Retrospective Cohort Study.
abstract: OBJECTIVE
  This retrospective cohort study was conducted to estimate the optimal interval for gastric cancer screening in Korean adults with initial negative screening results.
  
  
  METHODS
  This study consisted of voluntary Korean screenees aged 40 to 69 years who underwent subsequent screening gastroscopies after testing negative in the baseline screening performed between January 2007 and December 2011. A new case was defined as the presence of gastric cancer cells in biopsy specimens obtained upon gastroscopy. The follow-up periods were calculated during the months between the date of baseline screening gastroscopy and positive findings upon subsequent screenings, stratified by sex and age group. The mean sojourn time (MST) for determining the screening interval was estimated using the prevalence/incidence ratio.
  
  
  RESULTS
  Of the 293,520 voluntary screenees for the gastric cancer screening program, 91,850 (31.29%) underwent subsequent screening gastroscopies between January 2007 and December 2011. The MSTs in men and women were 21.67 months (95% confidence intervals [CI], 17.64 to 26.88 months) and 15.14 months (95% CI, 9.44 to 25.85 months), respectively.
  
  
  CONCLUSIONS
  These findings suggest that the optimal interval for subsequent gastric screening in both men and women is 24 months, supporting the 2-year interval recommended by the nationwide gastric cancer screening program.
authors: Department of Preventive Medicine, Jeju National University School of Medicine, Jeju, Korea.
authors: Jong-Myon
authors: JM
authors: Bae
authors: Korea Medical Institute, Seoul, Korea.
authors: Sang Yop
authors: SY
authors: Shin
authors: Department of Preventive Medicine, Jeju National University School of Medicine, Jeju, Korea.
authors: Eun Hee
authors: EH
authors: Kim
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012306:Risk; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000453:epidemiology
keywords: Early detection of cancer; Gastrointestinal endoscopy; Gastroscopy; Korea; Mass screening; Stomach neoplasms