Table 3 summarizes the results of the univariate and multivariate cox regression analysis for OS. The univariate analysis revealed that prognostic factors of OS were the same as those of PFS, including older age at surgery, advanced T stage, lymph node metastasis, poor tumor grade, positive PD-L1 IHC staining, and high PD-L1 mRNA expression. This evidence concerns the gene CD274 and metastatic malignant neoplasm in the lymph nodes.