Statistical analysis
tumor
TUMOR, METASTASES
All data were systematically collected to establish a comprehensive database. The data were analyzed by SPSS software for Windows, version 26.0 (SPSS Inc., Chicago, IL, USA). The Chi-square test was used to compare the differences in age, sex, pathologic stage, differentiation degree, tumor size, tumor location, and occurrence rate of metastases. The survival curves were calculated and compared by the Kaplan‒Meier method and the log-rank test. A 