Measurement of variables
tumor, death, Low‐, TCGA, tumors
TUMOR, TUMORS, SECONDARY
We collected variables of patients including age at diagnosis, gender, T/N/M classification, tumor grade, the amount of regional ELNs and PLNs, survival time and status. The tumor stage was based on the sixth edition of AJCC staging system, which was adapted to SEER‐derived patients diagnosed from 2004 to 2015. Low‐ and high‐grade tumors in TCGA were considered as grade I‐II and III‐IV in SEER database, respectively. The LNR was defined as the ratio of the amount of PLNs and ELNs. The LODDS was formulated by log [(PLNs +0.5) / (ELNs – PLNs +0.5)]. To avoid division by zero error, we added 0.5 to both numerator and denominator.The primary and secondary endpoints were OS and CSS, which were shown as “COD to site recode” and “SEER cause‐specific death classification” in SEER database, respectively. Of note, the data from the SEER and TCGA were downloaded on December 9, 2021.