Risk of Developing Metachronous Advanced Colorectal Neoplasia After Polypectomy in Patients With Multiple Diminutive or Small Adenomas

INTRODUCTION: Current post-polypectomy guidelines recommend a 3-year surveillance interval for >= 3 nonadvanced adenomas (NAAs) without discrimination between diminutive (1-5 mm) and small (6-9 mm) adenomas. We compared the risk of metachronous advanced colorectal neoplasia (ACRN) among these groups. METHODS: We studied 9,733 patients who underwent >= 1 adenoma removal and follow-up colonoscopic surveillance. Patients were classified based on baseline adenoma characteristics: group 1, 1-2 NAAs (n = 8,051); group 2, >= 3 diminutive NAAs (n = 293); group 3, >= 3 small NAAs (n = 258); and group 4, advanced adenomas (AAs) (n = 1,131). RESULTS: The mean age of the study population was 45.8 +/- 8.2 years. In group 4, most patients (94.5%) had 1 AA. The 3- and 5-year cumulative incidence rates of metachronous ACRN in groups 1, 2, 3, and 4 were 0.9%, 2.8%, 3.5%, and 4.0% and 3.1%, 10.7%, 15.1%, and 8.5%, respectively. Groups 2, 3, and 4 had a higher risk of metachronous ACRN than group 1. Compared with those for group 1, adjusted hazard ratios (95% confidence interval) for metachronous ACRN were 2.07 (1.16-3.68), 3.29 (1.94-5.56), and 2.73 (2.00-3.72) for groups 2, 3, and 4, respectively. However, this relationship was statistically insignificant between groups 2, 3, and 4. Compared with those for group 2, adjusted hazard ratios (95% confidence intervals) for groups 3 and 4 were 1.59 (0.76-3.30) and 1.32 (0.72-2.42), respectively, and 0.83 (0.47-1.46) for group 4 compared with group 3. The results of patients aged >= 50 years were identical to those of all patients. DISCUSSION: Risk of metachronous ACRN was not different between patients aged >= 50 years who underwent polypectomy of >= 3 diminutive NAAs, >= 3 small NAAs, and AA, thus supporting current guidelines that recommend a uniform surveillance interval for these lesions.