Prognostic significance of metastatic lymph node ratio in patients with gastric cancer / 中华普通外科杂志

ABSTRACT

Objective To evaluate the prognostic significance of metastastic lymph node ratio in patients with gastric cancer. Methods Clinical data of 319 patients with gastric cancer who underwent radical gastrectomy with at least 15 lymph nodes dissected per patient were analyzed retrospectively. Patients were divided into 4 groups according to the TNM staging system (1997,5th edition) pN0 (no positive lymph node), pN1(with 1～6 metastatic lymph nodes), pN2 group (with 7～15 metastatic lymph nodes), and pN3 group (with more than 15 metastatic lymph nodes), or into 4 groups according to the lymph node metastatic ratio rN0 group (without metastasis of lymph node), rN1 group (with a lymph node metastatic ratio of <30%), rN2 group (with a lymph node metastatic ratio of 30%～60%), and rN3 group ( with a lymph node metastatic ratio of >60%). Survival was determined by the Kaplan-Meier method and differences were assessed by the Log-rank test. Multivariate analysis was performed using the COX proportional hazard regression model in forward stepwise regression with SPSS 13.0. Results Kaplan-Meier survival analysis demonstrated that the metastatic lymph node ratio significantly influenced the postoperative survival time. According to the lymph node metastasis system 77 patients were in group 1, 109in group 2, 60 in group 3, and 73 in group 4. The 2-year survival rate was 84.4%,66.1%, 35.0%,and 15.1% respectively, 3-year survival rate was 80.5%,45.0%,15.0% and 5.5% respectively, and 4-year survival rate was 71.4%,33.0%,5.0% and 1.4% respectively. If cases with the same positive number of lymph node (pN) group were stratified futher by lymph node metastatic ratio, there were no significant differences in the 3-year survival rate among the new rN groups (P>0.05), but there was a great difference in the distribution of prognosis among different groups. COX proportional hazard regression model analysis showed that the metastatic lymph node ratio was an independent factor for poor prognosis. Lymph node metastatic ratio was closely related with the location, modality of the operation and infiltration depth. Conclusions The staging system based on metastatic lymph node ratio is more reliable than the system based on the number of metastatic lymph nodes in the prediction of the prognosis of gastric cancer.