Kaplan-Meier analysis for overall survival of young gastric cancer patients in the negative and positive lymph node metastasis groups (A), low and high lymph node ratio groups (B), and low and high log odds of positive lymph nodes groups (C). The AJCC N factor, LNR and LODDS were significantly associated with overall survival (all P<0.001). LNR, lymph node ratio; LODDS, log odds of positive lymph nodes.