[National Colorectal Cancer Screening Program: Fecal Immunochemical Testing vs. Colonoscopy]

Colorectal cancer (CRC) is a leading cause of morbidity and mortality worldwide, yet it is preventable through removal of adenomas and early detection. Screening is therefore a cornerstone of public health strategies. In Korea, fecal immunochemical testing (FIT) has been the mainstay of the national CRC screening program, while colonoscopy is gaining attention as a potential first-line method. FIT offers advantages of simplicity and low cost, yet its diagnostic accuracy for advanced adenomas and sustained compliance are limited. Colonoscopy, although invasive and more resource-demanding, enables direct visualization and removal of precancerous lesions, thereby offering stronger protection against CRC incidence and mortality. Current evidence indicates that each method has distinct strengths and limitations, and their effectiveness is influenced by participation rates, test quality, and healthcare infrastructure. The challenge for national policy lies in balancing clinical effectiveness, safety, participation, and economic feasibility. For Korea, advancing toward an optimal screening system will require improving FIT adherence, ensuring colonoscopy quality, and integrating individual risk factors into program design. Continuous evidence-based evaluation will be critical for guiding future screening policy.