Advanced synchronous adenoma but not simple adenoma predicts the future development of metachronous neoplasia in patients with resected colorectal Cancer

BACKGROUND: Patients with resected colorectal cancer remain at a high risk for developing metachronous neoplasia in the remnant colorectum. The aim of this study was to identify baseline clinical and colonoscopic features predictive of metachronous neoplasia after curative resection of colorectal cancer. METHODS: The baseline clinical and colonoscopic data and follow-up details of 503 patients who had colonoscopic surveillance after curative colorectal resection between January 2000 and October 2005 in a single tertiary institution were analyzed. Univariate and multivariate analyses were done to identify risk factors for metachronous adenoma. RESULTS: Metachronous adenomas were diagnosed in 176 patients (35.0%) and advanced adenomas in 39 (7.8%) during the follow-up period (35.7±20.9 ). Among the clinical and colonoscopic factors at baseline, advanced age (≥60 y) (odds ratio (OR)=3.64; 95% confidence intervals (CI), 1.55-8.52), the presence of advanced synchronous adenoma (OR=4.38; 95% CI, 1.77-10.85), and longer total follow-up period (OR=1.03; 95% CI, 1.01-1.04) were independently correlated with developing advanced metachronous adenoma. Patients who had synchronous tubular adenoma without advanced features at baseline were not found to have an increased risk for future development of advanced metachronous adenoma compared with those in the synchronous adenoma-free group (OR=1.75; 95% CI, 0.69-4.43, P=0.650). CONCLUSIONS: Our data showed that patients with advanced synchronous adenoma at baseline were identified to have an increased risk of advanced metachronous neoplasia during a longer follow-up period but those with tubular adenoma without advanced features at baseline were not.