Data source and patient selection
ONCOLOGY, DISEASES
The data was retrieved from the SEER database during 2010–2015 and analyzed retrospectively. External validation data was obtained from the Hangzhou TCM Hospital between January 2012 and December 2016. This research was carried out in line with the Helsinki Declaration. Participation in this study did not need written informed consent, as required by national law and institutional norms. The Ethics Committee of the Hangzhou TCM Hospital examined and approved the experiment involving human participants.The third edition of the International Classification of Diseases for Oncology (ICD-O-3) was used to identify cases of GNEC. 8012/3, 8013/3, 8041/3, 8042/3, 8043/3, 8044/3, 8244/3, and 8246/3 were the histological codes. The inclusion criteria were as follows: [
Flow diagram of the selection of eligible GNEC patients