[영문]Understanding the costs associated with early detection of disease is important for determining the fiscal implications of governmentfunded screening programs. We estimate the lifetime medical costs for patients with screendetected versus undetected polyps and earlystage colorectal cancer. Typically, cost?effectiveness studies of screening account only for the direct costs of screening and cancer care. Our estimates include costs for unrelated conditions. We applied the Kaplan?Meier Smoothing Estimator to estimate lifetime costs for beneficiaries with screendetected polyps and cancer. Phasespecific costs and survival probabilities were calculated from the Surveillance, Epidemiology, and End ResultsMedicare database for Medicare beneficiaries aged =65. We estimate costs from the point of detection onward; therefore, our results do not include the costs associated with screening. We used a modified version of the model to estimate what lifetime costs for these patients would have been if the polyps or cancer remained undetected, based on assumptions about the ‘lead time’ for polyps and earlystage cancer. For younger patients, polyp removal is cost saving. Treatment of earlystage cancer is cost increasing.