In the 8th edition of the tumor-node-metastasis (TNM) classification, the gastric cancer staging system includes two classifications: the clinical stage (cStage) and the postoperative pathologic stage. However, the correlation between the new cStage and overall survival has not been studied. Moreover, clinical N (cN) grade analysis is not included in the new clinical staging system. This study validated the prognostic value of cStage in the 8th edition of the TNM classification and the significance of N classification for pretreatment staging in gastric cancer.