Risk factors for lymph node metastasis in patients with submucosal invasive colorectal carcinoma

Purpose: This study was designed to determine the risk factors of lymph node (LN) metastasis in patients with submucosal invasive colorectal cancer (SICC). Methods: Between January 1998 and January 2009, we reviewed patients who had undergone radical colon resection with LN dissection for SICC. Results: There were 36 males and 40 females (mean age, 61.1 years; range, 35∼86 years). In the univariate analysis, the risk of LN metastasis was related to the depth (absolute and relative), lymphovascular invasion, tumor budding, and tumor differentiation (P<0.05). The relative depth by Kudo classification and lymphovascular invasion were significant predictors of LN metastasis both in univariate and multivariate analysis. In SICC with an absolute depth <1,800μm, no LN metastasis was detected. Regardless of the size of the SICC, tumors that invaded within the sm2 layer and had no lymphovascular invasion had no LN metastasis. Conclusion: In the SICC, lymphovascular invasion and depth of submucosal invasion are strong predictors of LN metastasis. If deep invasion exceeds sm2 and positive lymphovascular invasion exists in the resected specimen, additional colectomy with LN dissection appears to be necessary.