Global 
Deutschland Colon to Rectum
Gut. 2025;75(1):72-80
Comparative risk of high-risk neoplasia after polypectomy among individuals aged below 50 years versus 50 years and older
Background: Limited evidence supports colonoscopy surveillance practices among individuals aged < 50 years.
Objective: To compare the risk of polyp recurrence and colorectal cancer (CRC) among young and old adults after polypectomy.
Design: The authors prospectively examined the risk of metachronous high-risk neoplasia, including high-risk adenoma, high-risk serrated polyp (SP) and CRC, according to index colonoscopy findings among individuals aged < 50 years and ≥ 50 years who had received ≥ 1 follow-up colonoscopy in the Mass General Brigham Colonoscopy Cohort (2007–2023). They used a multivariable-adjusted Cox proportional hazards model to calculate HRs.
Results: The authors identified 37,576 adults without polyps, 26,693 with adenomas and 15,425 with SPs (including 8303 with synchronous adenomas and SPs). Among these 10,977 (29.2%), 3385 (12.7%) and 2659 (17.2%) were diagnosed before age 50 years, respectively. The associations between index polyp findings and subsequent risk of high-risk neoplasia were stronger for age < 50 years than ≥ 50 years; however, such differences disappeared (pheterogeneity > 0.05) once the analysis was restricted to index colonoscopy for screening purposes only. Among screened individuals, in both age groups, the association was particularly strong for individuals with index high-risk lesions and peaked at 3 years after polypectomy, with HRs (95% CI) of 4.60 (3.63–5.84) and 5.59 (3.89–8.03) for young adults with index high-risk adenoma and high-risk SPs, respectively.
Conclusion: Patients undergoing polypectomy at a screening colonoscopy below age 50 years exhibited a similarly increased risk of metachronous neoplasia as those aged ≥ 50 years, suggesting that current surveillance guidelines developed in old adults may apply to young adults.