Trends in colorectal cancer incidence according to an increase in the number of colonoscopy cases in Korea

BACKGROUND The incidence of colorectal cancer (CRC) and preinvasive CRC (e.g., early colon cancer and advanced adenoma) is gradually increasing in several countries. AIM To evaluate the trend in incidence of CRC and preinvasive CRC according to the increase in the number of colonoscopies performed in Korea. METHODS This retrospective cohort study enrolled Korean patients from 2002 to 2020 to evaluate the incidence of CRC and preinvasive CRC, and assess the numbers of diagnostic colonoscopies and colonoscopic polypectomies. Colonoscopy-related complications by age group were also determined. RESULTS The incidence of CRC showed a rapid increase, then decreased after 2012 in the 50-75 year-age group. During the study period, the rate of incidence of preinvasive CRC increased at a similar level in patients under 50 and 50-75 years of age. Since 2009, the increase has been rapid, showing a pattern similar to the increase in colonoscopies. The rate of colonoscopic polypectomy in patients aged under 50 was similar to the rate in patients over 75 years of age after 2007. The rate of complications after colonoscopy and related deaths within 3 mo was high for those over 75 years of age. CONCLUSION The diagnosis of preinvasive CRC increased with the increase in the number of colonoscopies performed. As the risk of colonoscopy-related hospitalization and death is high in the elderly, if early lesions at risk of developing CRC are diagnosed and treated under or at the age of 75, colonoscopy-related complications can be reduced for those aged 76 years or over.