Abstract: Objective To investigate the characteristics of lymph node sorting and risk factors of metastasis in group No.6 lymph node of lower gastric carcinoma.To provide the data support for standardizing lymph node grouping and harvested in laparoscopic radical distal gastrectomy.Methods This study included 66 patients with lower gastric carcinoma who underwent laparoscopic D2 radical gastrectomy in the department of Gastrointestinal Surgery,Union Hospital,Tongji Medical College,Huazhong University of Science and Technology from January 2017 to December 2017.Lymph node sorting of each gastric cancer sample was performed according to the scope of D2 dissection.The total number of harvested lymph nodes,total number of metastatic lymph nodes,proportion of patients with lymph node metastasis and lymph node metastasis rate were calculated in each group such as No.1、No.3、No.4sb、No.4d、No.5、No.6、No.7、No.8a、No.9、No.11p and No.12a.Clinicopathological data were recorded:gender,age,depth of invasion,tumor size,degree of differentiation,nerve invasion,vascular invasion,body mass index,HER2 expression,cancer nodule surrounding the tumor and tumor location.The characteristics of lymph node sorting in group No.6 were analyzed and concluded.Univariate and multivariate analysis of risk factors for lymph node metastasis in group No.6 were performed.Results The proportion of patients with lymph node metastasis in group No.6 was 18/66(27.3%),and the rate of lymph node metastasis was 60/233(25.8%).Univariate analysis showed that the depth of invasion(χ2=7.153,P=0.007),nerve invasion(χ2=8.503,P=0.004),vascular invasion(χ2=5.677,P=0.017),HER2 expression(χ2=4.979,P=0.026)and cancer nodule surrounding the tumor(χ2=5.408,P=0.020) were significantly associated with lymph node metastasis in group No.6(P< 0.05).Lymph node metastasis in group No.3(χ2=5.432,P=0.020),group No.7(χ2=12.726,P=0.000),group No.8a(χ2=10.615,P=0.001) and group No.9(χ2=7.787,P=0.005) were closely correlated with lymph node metastasis in group No.6(P<0.05).Multivariate Logistic regression analysis showed that cancer nodule(OR=15.648，95%CI:2.946~83.118)and HER2 expression(OR=11.706，95%CI:2.018~67.890) were independent risk factors for lymph node metastasis in group No.6(P<0.05).Conclusion The attention should be paid to lymph node metastasis and sorting in group No.6 in laparoscopic radical distal gastrectomy.According to the lymph node metastasis of group No.6,the scope of lymph node dissection should be appropriately expanded.

Key words: lower gastric carcinoma, lymphatic metastasis, group No.6 lymph node, lymph node sorting