Feng, Yifan
Wang, Ye
Xie, Yangqin
Wu, Shuwei
Li, Yuyang
Li, Min
Article History
Received: 19 December 2020
Accepted: 16 April 2021
First Online: 23 April 2021
Declarations
:
: All cases extracted from the SEER database do not contain any personally identifying information. The external validation set are available to every researcher since all the patients were authorized by Anhui Medical University Ethics Committee when they signed to obey the data use agreement. This study was approved by Anhui Medical University Ethics Committee. The need of informed consent was waived by Anhui Medical University Ethics Committee for this retrospective study.
: NOT APPLICABLE.
: The authors declared that no competing interest exists.