Trends in the Performance of the Korean National Cancer Screening Program for Gastric Cancer from 2007 to 2016

The Korean National Cancer Screening Program (KNCSP) has implemented two screening methods for gastric cancer-upper gastrointestinal series (UGIS) and endoscopy-for Koreans aged ≥40 years. We aimed to assess performance trends for both screening methods. The KNCSP database was used to evaluate individuals who underwent screening from 2007 to 2016. The final gastric cancer diagnosis was ascertained by linking with the Korean Central Cancer Registry. We conducted a prospective, cross-sectional analysis to estimate performance indicators of gastric cancer screening by UGIS and endoscopy, stratified by sociodemographic factors. We found that screening rates for gastric cancer increased from 28% to 51.7% between 2007 and 2016, and that the rate of endoscopy use for gastric cancer screening increased sharply. Cancer detection rates (CDR) of UGIS and endoscopy were 0.41 and 2.25 per 1,000 screens in 2007-2008 and 0.26 and 1.99 in 2015-2016, respectively. Interval cancer rates (ICR) per 1,000 negative screenings were 1.33 (2007-2008) and 1.21 (2015-2016) for UGIS and 1.14 (2007-2008) and 0.88 (2015-2016) for endoscopy. The sensitivity of UGIS decreased from 23.6% (2007-2008) to 17.6% (2015-2016), whereas that of endoscopy increased from 66.4% (2007-2008) to 69.3% (2015-2016). Specificity was maintained at >99% for both methods over the study period. The use of endoscopy for gastric cancer screening within the KNCSP has increased. Endoscopy has higher CDR, sensitivity, and specificity, and lower ICR estimates than does UGIS.