Funding for this research was provided by:
Special Research Projects for Capital Health Development (2014-1-2151)
Beijing Hope Run Special Fund of Cancer Foundation of China (LC2017L01)
Received: 12 March 2020
Accepted: 17 January 2021
First Online: 26 January 2021
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of the National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (Beijing, China). The SEER database is publicly available and provides de-identified case data. Because of the analysis used anonymous clinical data, written informed consent from subjects was waived.
: Not applicable.
: All authors declare no conflicts of interest related to this article.