Abstract
PURPOSE OF REVIEW: Colorectal cancer (CRC) screening is recommended to reduce CRC mortality. This review outlines key factors to consider when recommending screening, including disease burden, screening benefits and harms, and remaining knowledge gaps. RECENT FINDINGS: In response to increasing rates of CRC incidence among younger (age < 50 years) adults, the American Cancer Society published guidelines in May 2018 recommending average-risk CRC screening beginning at age 45 (vs. 50) years. Rates of young-onset CRC have increased in the USA since the early 1990s. However, there is very little empirical evidence of screening effectiveness in younger adults, and few studies have reported harms of routine screening in this age group. Further, we know little about the natural history of CRC in younger adults. Uncertainty surrounding the efficacy of CRC screening in younger adults suggests the benefits may be small. Precision cancer screening-or modified screening regimens based on risk-may improve the balance of screening benefits and harms beyond conventional age-based strategies.