Article History
Received: 3 October 2019
Accepted: 18 May 2020
First Online: 24 May 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of the Samsung Medical Center, which waived the written informed consent because of the study’s retrospective design and was conducted in accordance with the tenets of the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.