Funding for this research was provided by:
National Cancer Center (NCC 2011520-1)
Received: 17 August 2020
Accepted: 29 October 2020
First Online: 13 November 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of the National Cancer Center, Korea (approval number NCC2020-0166). Research was conducted in accordance with the principles of the 1964 Declaration of Helsinki and its later amendments. The requirement for informed consent was waived owing to the retrospective nature of the study.
: Not applicable.
: The authors declare that they have no competing interests.