Received: 18 February 2021
Accepted: 16 August 2021
First Online: 21 August 2021
: The study was approved by the Institutional Review Board (IRB) of National Cancer Center (IRB No. NCC 2018–0096). The requirement for informed consent was waived because the data from the Korean National Health Insurance System (NHIS, dataset number, REQ000019166) were anonymized. All methods were carried out in accordance with relevant guidelines and regulations.
: Not Applicable.
: All the authors had no competing interests in this study.