Indication for Endoscopic Resection of Submucosal Colorectal Carcinoma: Special Reference to Lymph Node Metastasis

We investigated the relationship between histological factors and lymph node metastasis in 77 lesions with submucosally invasive colorectal carcinomas to establish useful criteria for lesions in which endoscopic treatment alone results in cure of malignancy. There were positive correlations between histological factors, including the level of invasion, the histologic grade, presence or absence of lymphatic invasion, presence or absence of budding, and lymph node metastasis (p < 0.05, p < 0.05, p < 0.005, p < 0.01). The presence or absence of venous invasion did not influence lymph node metastasis. Laparoscopic surgery involving lymph node dissection should be indicated for sm1 carcinoma lesions with unfavorable histological factors. In lesions diagnosed as sm2 or sm3 prior to resection, intestinal resection involving lymph node dissection by laparoscopic surgery should be directly performed without endoscopic resection. In treating submucosally invasive colorectal carcinomas, the level of invasion can be clinically diagnosed, consequently endoscopic resection should be initially performed when lesions are evaluated as sm1 prior to resection. When histological investigation reveals sm1 carcinoma with histologic grade I (well-differentiated) or II (moderately-differentiated), and the absence of lymphatic invasion and budding, endoscopic treatment alone is sufficient.