Risk factors for lymph node metastasis in submucosally invasive colorectal cancer.

Abstract

542 Background: The aim of this study was to identify risk factors for lymph node metastasis (LNM) in submucosally invasive colorectal cancer (SICC) that might be used in selecting patients for local excision. Methods: Records were reviewed from consecutive patients who had undergone curative resection of SICC at the Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China, between 2006 and 2013. Clinical features such as age, gender, tumor size, and location were reviewed. Histopathologic examinations including tumor growth type, growth pattern at the invasive front, histopathological type, depth of tumor invasion, tumor budding, lymphovascular invasion, and neural invasion were performed. The expression of E-cadherin, p53, and Ki-67 were examined by immunohistochemistry. The association between the clinicopathologic factors and LNM was evaluated. Results: A total of 265 patients (140 men and 125 women) treated for SICC were included. The overall LNM rate was 12.8%. The incidence of LNM was significantly associated with growth pattern at the invasive front (p=0.028), tumor budding (p=0.006), histopathological type (p<0.001), and lymphovascular invasion (p<0.001). Other clinicopathologic and immunohistochemical factors were irrelevant to LNM. In multiple variable logistic analysis, histopathological type, and lymphovascular invasion were the two independent risk factors of LNM (p=0.015 and p=0.007, respectively). Conclusions: Histopathological type and lymphovascular invasion are significant independent risk factors for LNM in SICC. Careful selection for local excision in SICC should be considered.