Novel Risk Stratification for the Recurrence after Endoscopic Resection of Advanced Colorectal Adenoma

Abstract

Introduction: Advanced colorectal adenoma (ACA) is defined as colorectal adenomas with at least one of three categories showing 1 cm or greater, villous component, and high-grade dysplasia. ACA has a high risk of developing colorectal cancer, and the recurrence rate is relatively high after the endoscopic resection. The aims of this study were to assess the clinical outcomes of ACA after endoscopic resection and identify risk factors of recurrence.

Methods: From January 2005 to December 2011, a total of 2,431 patients who underwent endoscopic resection for ACA in Seoul National University Hospital were retrospectively reviewed. Among them, 1,502 patients were excluded due to synchronous colorectal cancers, familial colorectal cancers, inflammatory bowel diseases, previous colorectal resection, and no follow-up colonoscopy. The primary outcomes were local recurrence and metachronous advanced neoplasm. Local recurrence was defined as detection of adenoma at the same site of previous resection. Metachronous advanced neoplasms were defined as detection of at least 1 ACA and/or adenocarcinoma at a follow-up colonoscopy.

Results: A total of 1,218 cases of ACA detected in 929 patients were enrolled. Median follow-up duration was 28.5 months (range, 12.8-51.7). Complete resection was accomplished in 1,206 (99.0%) cases. Local recurrence and metachronous advanced neoplasm occurred in 45 (3.7%) and 170 (13.6%) cases, respectively. Cumulative rates of local recurrence in cases with 1 and 2-3 categories of ACA were 2.2% and 7.7% at 3 years, respectively. Cumulative rates of metachronous advanced neoplasm in cases with 3 or more adenomas were 18.6% and 22.5% at 3 years, respectively. Independent risk factors of local recurrence were ACA with 2 or 3 categories (hazard ratio [HR] 2.56, 95% confidence interval [CI] 1.36–4.81

p=0.004), laterally spreading tumor (HR 2.93, 95% CI 1.48–5.81

p=0.002), and piecemeal resection (HR 7.04, 95% CI 3.51–14.13

p<0.001). Independent risk factors of metachronous advanced neoplasm were male sex (HR 1.66, 95% CI 1.03–2.67

p=0.038), 3 or more adenomas (HR 2.52, 95% CI 1.70–3.74

p<0.001), and 3 or more of ACA (HR 1.43

95% CI 1.01–2.04

p=0.049).

Conclusion: ACA with 2 or 3 categories could show higher local recurrence rate after the endoscopic resection than that in ACA with 1 category, which suggests the novel risk stratification of ACA according to the number of categories at index colonoscopy.