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)
the Focused Research and Development Program of Shandong Province (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.