Effectiveness of the Korean National Cancer Screening Program in Reducing Colorectal Cancer Mortality

Whether colorectal cancer (CRC) screening with a fecal immunochemical test (FIT) reduces mortality remains unclear. In South Korea, CRC screening with a FIT for individuals aged ≥ 50 years has been part of the Korean National Cancer Screening Program (KNCSP) since 2004. The aim of this study was to evaluate the effectiveness of the KNCSP in reducing CRC-specific mortality.

We conducted a nested case-control study using cohort-based data derived from the KNCSP database. The cohort included 5,944,540 colorectal cancer-free individuals aged ≥ 50 years as of 2004. Individuals who died after CRC diagnosis were defined as cases (n = 29,992) and their sociodemographic characteristics were matched to those of the selected controls. The effects of screening exposure, frequency, and time interval on CRC-specific mortality were analyzed according to age group. Conditional logistic regression analysis was performed.

Compared with individuals who had never been screened, those who had ever been screened showed an OR of 0.74 (95% CI, 0.71-0.76) for CRC-specific mortality. CRC-specific mortality decreased as the number of screenings increased. Similar results were observed for those aged 50-79 years; however, the results for those aged 75-79 years were not statistically significant. Moreover, those aged ≥ 80 years had the opposite results.

CRC mass screening using FIT is effective for individuals aged 50-74 years; therefore, this study suggests that countries considering introducing national CRC screening implement FIT for those within this age range.