Risk of developing metachronous advanced colorectal neoplasia after colonoscopic polypectomy in patients aged 30 to 39 and 40 to 49 years

Background and Aims: Current guidelines define postpolypectomy surveillance intervals in patients aged >= 50 years. The risk of metachronous colorectal neoplasia (CRN) and the optimal postpolypectomy surveillance interval in patients aged <50 years remain unclear. We compared the risk of metachronous CRN in patients aged 30 to 39, 40 to 49, and >= 50 years. Methods: We studied patients who underwent >= 1 adenoma removal between 2010 and 2014 and follow-up colonoscopic surveillance until 2017. Results: Among 10,014 patients studied, 3242, 4606, and 2166 were 30 to 39, 40 to 49, and >= 50 years old, respectively. After high-risk adenoma removal, the 3-year risk of metachronous advanced CRN (ACRN) in patients aged 30 to 39 and 40 to 49 years was lower than inpatients >= 50 years old (1.9% and 3.6% vs 8.1%, respectively; P<.001 and .008). After low-risk adenoma removal, the 5-year risk of metachronous ACRN in patients aged 30 to 39 and 40 to 49 years was lower than in patients >= 50 years old (2.8% and 3.3% vs 5.9%, respectively; P = .010 and .031). The risk of metachronous ACRN or >= 3 adenomas in patients aged 30 to 39 years was significantly lower than in patients aged 40 to 49 years. Age remained significantly associated with the risk of metachronous ACRN despite adjustments for potential confounders. Conclusions: The risk of metachronous ACRN was lower in patients aged <50 years than in those aged >= 50 years; thus, the postpolypectomy surveillance interval may be extendable to >3 and 5 years in high-risk and low-risk adenoma groups, respectively, in patients aged <50 years.