Current Status of the National Cancer Screening Program in Korea: History, Achievements, and Future Directions.

Cancer is the leading cause of morbidity and mortality worldwide. To reduce this burden, the Korean government established the National Cancer Screening Program (NCSP) in 1999, initially offering stomach, breast, and cervical cancer screening to Medical Aid Program (MAP) beneficiaries. By 2019, the NCSP had broadened both its eligible population and the range of cancers screened-stomach, liver, cervical, breast, colorectal, and lung-for both MAP recipients and health insurance beneficiaries. Since its inception, participation and adherence to recommended screening have risen steadily, driven by nationwide policy initiatives and expanded access. Over the past 2 decades, the NCSP has played a key role in reducing the incidence of stomach, liver, colorectal, and cervical cancers while increasing detection at precancerous stages, especially for cervical and colorectal cancers. Five-year relative survival rates for major cancers-most notably stomach, colorectal, and breast-have also improved substantially. Accumulated evidence, including cancer detection rates, stage distribution at diagnosis, and mortality reduction, underscores the program's effectiveness in facilitating early detection and reducing cancer-specific deaths. Notably, Korea's mortality-to-incidence ratio for major cancers remains well below the Organization for Economic Co-operation and Development average, illustrating the impact of the nation's comprehensive cancer control strategies. Continued research, surveillance, and refinement of evidence-based screening guidelines will be critical to further enhancing the efficiency and effectiveness of the NCSP.