Zhang, Zhao
Wu, Hongliang
Yang, Tong
Wu, Yaohai
Yu, Nengwang https://orcid.org/0000-0002-9131-8166
Xu, Zhonghua
Funding for this research was provided by:
the Focused Research and Development Program of Shandong Province (2017GSF18162, 2017GSF18130)
the Natural Science Foundation of Shandong Province (ZR2018MH024)
Article History
Received: 15 March 2020
Accepted: 26 August 2020
First Online: 3 September 2020
Ethics approval and consent to participate
: We obtained the permission to access the SEER database with the ID number 10616-Nov2018 via Internet access method. Ethical approval was waived by the local ethics committee, as SEER data is publicly available, de-identified.
: Not applicable.
: The authors declare that they have no conflict of interest.