To study the value of metastatic lymph node radio (rN) and pathological lymph node stage (pN) in evaluating the prognosis of patients after radical gastric cancer.

The clinicopathological data of 491 patients who underwent radical gastrectomy in Tantai Yantaishan Hospital from Jan. 2013 to Dec. 2017 were retrospectively analyzed. X-tile software was used to group the metastatic lymph node radio by rN. According to the number of lymph node metastasis, pN stage was performed. The correlation between metastatic lymph node radio and other clinicopathological factors was assessed. The metastatic lymph node radio and the pathological lymph node stage in evaluating the prognosis of patients after radical gastric cancer were compared.

(1) X-tile analysis showed that the best cut-off values for the metastatic lymph node radio in this study were 0.14 (14%) and 0.63 (63%) . (2) According to the cut-off value, the 491 patients included in the study were divided into rN1 (256 cases) , rN2 (160 cases) , and rN3 (75 cases) three subgroups. The results of the analysis of differences showed that there were significant differencesbetween the groups in terms of tumor diameter, tumor location, surgical resection range, stage, lauren classification, degree of differentiation, pT, pN, vascular cancer emboulus, nerve invasion, and pathological TNM staging groups. (3) Comparison of rN and pN staging in evaluation of the prognosis of patients after radical gastric cancer: ①Kaplan-Meier survival analysis results showed that rN was better than pN. ② Both single factor and multivariate cox analysis showed that rN was an independent risk factor for the prognosis of gastric cancer. In univariate analysis, rN group HR=3.18 (95%CI 2.63-3.84, P<0.001) , pN stage HR=1.88 (95%CI 1.66-2.15, P<0.001) ; rN group HR=2.21 in multivariate analysis (95%CI 1.73-2.82, P<0.001) , pN staging HR=1.31 (95%CI 0.95-1.79, P=0.095) . ③The time-dependent ROC analysis showed that the prognostic ability of rN was better than pN staging before 52 months of postoperative follow-up, and pN staging was more advantageous after 52 months. ④The Lauren classification was used as a stratification factor for stratified analysis. The Kaplan-Meier survival curve indicated that rN was better than pN staging in intestinal, mixed and diffuse gastric cancer, and the AUC curve showed the prediction of rN in patients with mixed and diffuse gastric cancer was better than pN staging, while pN staging performance was slightly better in patients with intestinal gastric cancer.

rN is an independent factor affecting the prognosis of patients after radical gastric cancer surgery. When judging the prognosis of patients within 52 months after radical gastric cancer, rN has a better prognostic value than pN. In patients with mixed and diffuse gastric cancer in the Lauren classification, rN shows better prognostic value.

Gastric neoplasms; Radical resection; Metastatic lymph node radio; Lymph node stage; Lauren classification