Funding for this research was provided by:
Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support (PX2019038)
Science Foundation of Peking University Cancer Hospital (2017–18, 18-02)
Received: 19 September 2019
Accepted: 7 August 2020
First Online: 24 August 2020
Ethics approval and consent to participate
: The study was exempted from ethical review by the Beijing Cancer Hospital. We obtained the data agreement and downloaded the files directly from the SEER website in accordance with SEER requirements. The reference number was 15586-Nov2016.
: Not applicable.
: The authors declare that they have no competing interests.