Risk Factors for Lymph Node Metastasis after Endoscopic Resection for Early Colorectal Cancer

ABSTRACT

BACKGROUND/AIMS: Although endoscopic resection is widely used for the treatment of early colorectal cancer, the risk factors for lymph node metastasis are not clear. This study was designed to determine the risk factors for lymph node metastasis in patients with colorectal cancer who are treated by endoscopic resection. METHODS: The medical records of patients with histologically-proven early colorectal cancers who were treated by endoscopic resection between January 2002 and September 2008 were retrospectively reviewed. Information regarding the demographic data of patients and the clinicopathologic characteristics were recorded and analyzed. RESULTS: Twenty-nine patients who underwent subsequent surgical treatment after endoscopic resection for early colorectal cancer were enrolled in this study. Six patients (20.7%) had lymph node metastases on surgical pathologic examination. The predictive factors for lymph node metastasis were tumor morphology (non-polypoid flat tumors [p=0.019]), absence of background adenomas (p=0.033), and deep submucosal invasion > or = 2,000 um (p=0.012). Unexpectedly, the presence of vascular invasion was not associated with lymph node metastasis. CONCLUSIONS: The presence of vascular invasion might not be an absolute indication for additional surgical treatment of early colorectal cancer; however, deep submucosal invasion, accompanied by a gross tumor with a non-polypoid flat morphology, and the absence of background adenomas are potential risk factors for lymph node metastasis.