The risk factors for regional lymph node metastasis of mismatch repair deficient colorectal cancer

Abstract

Objective: To explore the risk factors for regional lymph node (RLN) metastasis in colorectal cancer patients with mismatch repair deficiency (dMMR). Methods: The data of 357 dMMR colorectal cancer patients who underwent surgery in National Cancer Center from January 2012 to December 2016 was retrospectively analyzed. Univariate and multivariate analysis were used to identify the risk factors for RLN metastasis. Results: Among the 357 patients, 204 were male and 153 were female, 61.6% (220/357) lesion located in right half colon, while the other 16.2% (58/357) located in rectum. Univariate analysis showed that tumor size, differentiation, lymphovascular invasion, tumor deposit, postoperative pathologic T stage (pT), the number of negative lymph nodes and the expression of the MSH6 protein were significantly associated with RLN metastasis (P<0.05). All of the patients with well differentiation tumors (15 patients) or staged pT1 (13 patients) had no RLN metastasis. Multivariate analysis showed that tumor differentiation (OR=2.582, 95%CI=1.567-4.274, P<0.001), pT (OR=3.778, 95%CI=1.448-12.960, P=0.015) and the expression of MSH6 protein (OR=2.188, 95%CI=1.159-4.401, P=0.021) were independent risk factors for RLN metastasis. Conclusions: The postoperative pT stage, tumor differentiation and the expression of MSH6 protein are independent risk factors for RLN metastasis of dMMR colorectal cancer. Preoperative assessment of these factors may further improve the accuracy of predicting the risk of RLN metastasis.