Risk Factors for Residual Cancer and Lymph Node Metastasis After Noncurative Endoscopic Resection of Early Colorectal Cancer

BACKGROUND: Endoscopic resection could be a curative treatment for early colorectal cancer without the possibility of lymph node metastasis. However, if the resection margin is positive, and there is a risk of lymph node metastasis, additional surgery should be performed. OBJECTIVE: The aim of this study was to investigate the characteristics of patients who underwent additional surgery to determine risk factors associated with residual tumor and lymph node metastasis. DESIGN: This study is a retrospective analysis. SETTINGS: This study was conducted at a tertiary academic hospital. PATIENTS: We evaluated 85 patients who underwent additional surgery with curative intent after endoscopic resection for early colorectal cancer at the Samsung Medical Center, Seoul, South Korea, between January 2001 and April 2010. MAIN OUTCOME MEASURES: We identified risk factors associated with residual tumor or lymph node metastasis in surgical specimens after noncurative endoscopic resection for early colorectal cancer. RESULTS: Among 85 patients who underwent additional surgery after noncurative endoscopic resection, 76 (89.4%) had submucosal invasion greater than 1000 mu m. Twenty-one (24.7%) and 25 patients (29.4%) had a positive lateral or vertical resection margin, and 11 patients (12.9%) had inadequate lifting sign. After additional surgery, patients were divided into 2 groups according to the presence or absence of residual tumor and/or lymph node metastasis. There was no significant difference between the groups in positive lateral margin, but there was a significant difference in positive vertical margin (p = 0.015 with an OR of 15.02). In patients with inadequate lifting sign, the OR was 13.68 (p = 0.013). LIMITATIONS: This study was limited by its retrospective nature. CONCLUSION: There is a greater need for additional surgery in cases with positive vertical resection margin or inadequate lifting sign, because the risk of residual tumor and lymph node metastasis is higher than in other cases.