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.