[Early-onset Colorectal Cancer].

The incidence of colorectal cancer (CRC) is increasing among young adults in several countries including the United States. Early-onset colorectal cancer (EO-CRC) is heterogenous group and appears to have a distinct clinical, pathologic, and molecular presentation compared to CRC diagnosed in older patients. EO-CRC patients tend to be diagnosed at later stage and with symptomatic disease. Tumors arise predominantly in the distal colon and rectum and have poorer histological features. Microsatellite and chromosome stable molecular pathway is frequently observed in EO-CRC. Survival data of EO-CRC is conflicting and younger patients tend to be treated more aggressively. It is important to identify high risk and have them screened appropriately to address increasing EO-CRC. Screening and treatment strategies for EO-CRC should be developed through further investigation of molecular mechanism and various environmental risk factors. In Korea, EO-CRC and late-onset CRC have both declined in recent several years, probably due to many screening colonoscopies in young population. Close observation and analysis of EO-CRC in Korea is necessary.