Received: 30 April 2020
Accepted: 2 February 2021
First Online: 9 February 2021
Ethics approval and consent to participate
: This study was approved by the institutional review board of Sun Yat-sen University Cancer Center as a retrospective study, and the requirement for informed consent was waived. All procedures performed in studies involving human participants were in accordance with the ethical standards of the1964 Helsinki declaration and its later amendments.
: The authors declare that they have no competing interests.