Since 2004, the National Colorectal Cancer Screening Program has been annually conducting fecal occult blood test (FOBT) for men and women aged 50 and older. Person with FOBT-positive have recommend double contrast barium enema (DCBE) or colonoscopy as additional screening.

Therefore, the participation rate of FOBT as the first screening test and additional tests as the second screening test are considered to be an important index. In particular, it was necessary to identify the current problems such as non-compliance due to loss of follow-up, delayed further testing, delayed diagnosis due to a lack of understanding of test results.

The purpose of this study was to investigate the current state of follow-up examination of national colorectal cancer screening, factors affecting participation in screening, and analyze the performance according to screening compliance. This study may contribute to provide base data for developing the strategy to improve national colorectal cancer screening.