Risks of colorectal advanced neoplasia in young adults versus those of screening colonoscopy in patients aged 50 to 54 years

Background and Aim: The role of screening or diagnostic colonoscopy to detect advanced neoplasia in young cohorts of age < 50 is unclear. This study compared the risk of colorectal neoplasia in a young age cohort against that in 50–54s screening cohort. Methods: A multi-center retrospective study was conducted at 14 university hospitals to compare the detection rates of neoplasia and advanced neoplasia in screening or diagnostic colonoscopy in the young cohort of < 50s against those in screening colonoscopy in the 50–54s cohort. Results: Among 10 477 eligible subjects, 9765 subjects were enrolled after excluding 712 subjects. Advanced neoplasia detection rates in the young screening cohort was significantly lower than that in the 50–54s screening cohort (5.9% vs 9.3%, P < 0.001). Compared with 50–54s screening cohort, the risk of advanced neoplasia was significantly reduced by 23%, 53%, and 54% in the 45–49s, 40–44s, and 20–39s screening cohorts, respectively. The detection rates of advanced neoplasia in the young diagnostic cohort was 5.0%, which was much lower than 11.8% in 50–54s screening cohort (P < 0.001). Compared with the 50–54s screening cohort, the risk of advanced neoplasia was significantly reduced by 50%, 66%, and 71% in the 45–49s, 40–44s, and 20–39s diagnostic cohorts, respectively. Conclusions: Colonoscopy to detect advanced neoplasia in young adults aged < 50 years should be reconsidered as their risk of advanced neoplasia on screening or diagnostic colonoscopy was much lower than those of 50–54s screening cohort; however, colonoscopy screening may be justified for high-risk 45–49s cohorts.