Colorectal cancer (CRC) is one of the leading causes of cancer
death in industrialized nations [1] and is the fourth greatest cause
of cancer death in Korea [2]. Screening for the early detection and
prevention of CRC can substantially reduce the morbidity and
mortality associated with the disease [3,4]. The CRC screening
guidelines of many professional societies recommend that
screening begin at an age of 50 years for asymptomatic,
average-risk individuals, with various combinations of fecal
occult-blood testing, flexible sigmoidoscopy, barium enema,
and colonoscopy [5–7]. The main reason for the choice of age
50 as the primary threshold for screening is the dramatic increase
in the incidence of CRC during the sixth decade of life [8]. Previous