Colorectal cancer is the third most common cancer and the fourth leading cause of cancer death in Korea. Colonoscopic screening with removal of adenomas is an effective strategy for reducing the incidence and mortality of colorectal cancer. This study was conducted to investigate predictable factors of early colorectal cancer (ECC) in patients with advanced adenoma (AA), tumor in situ (Tis), and submucosal (SM) cancer diagnosed after colonoscopic polypectomy.

Between August 2003 and June 2012, a total of 1,001 patients who underwent colonoscopic polypectomy in Jeju National University Hospital were enrolled in this study.

Patients were classified into four groups; non-AA, AA, Tis, and SM cancer. Compared to the AA group, the ECC group (n=50) had large adenoma size (12.2±5.9 mm vs . 15.3±6.5 mm, P <0.01), distal location (39.3% vs. 52.0%, P =0.05) and diabetes mellitus (13.1% vs . 25.0%, P =0.04). However, age, sex, body mass index, the mean number of polyps, and morphological features (polypoid vs . nonpolypoid lesions) were not significantly different between the AA and ECC groups. In multivariate analysis, adenoma size >15 mm (odds ratio [OR], 4.49; 95% confidence interval [CI] 2.40-8.38), distal location (OR, 2.59; 95% CI, 1.33-5.05), and diabetes mellitus (OR, 2.10; 95% CI, 1.07-4.43) were significantly associated with ECC. Of the 12 patients with SM cancer, 5 underwent additional operations and had no remnant carcinoma.

Predictable factors of ECC after colonoscopic polypectomy may be adenoma size >15 mm, distal location and diabetes mellitus.