OBJECTIVETo evaluate the prognostic value of metastatic lymph node ratio (MLR) for gastric cancer patients with less than 15 lymph nodes dissected.

METHODSClinical data of 610 gastric cancer patients undergoing operation in Tianjin Cancer Hospictal from January 2003 to July 2007 were analyzed retrospectively. Patients were divided into two groups: <15 lymph nodes dissected group (n=320) and ≥ 15 lymph nodes dissected group (n=290). MLR was classified based on the following intervals: rN1 ≤ 10%, rN2 10%-30%, rN3 30%-60% and rN4 >60%. Survival was determined by Kaplan-Meier method and difference was assessed by Log-rank test. Multivariate analysis was performed using Cox proportional hazard regression model. Survival rates were compared between two groups in pN and rN stages respectively.

RESULTSIn <15 nodes group, all the survival differences among various rN stages were not significant (all P>0.05), while in same rN stage, all the survival differences among various pN stages were not significant (all P>0.05). Significant differences of 5-year cumulative survival rates were found between the two groups in pN2 and pN3a stage patients (both P<0.05) while no significant differences were found among different rN stages (all P>0.05). Multivariate analysis demonstrated rN stage was an independent prognostic factor for gastric cancer patients with <15 lymph nodes dissected (P=0.012, RR=1.617, 95%CI:1.111-2.354).

CONCLUSIONThe rN staging system based on MLR can predict the prognosis of gastric cancer patients with less than 15 lymph nodes dissected.