Received: 6 May 2020
Accepted: 27 July 2020
First Online: 5 August 2020
Ethics approval and consent to participate
: This retrospective study was performed in accordance with the Declaration of Helsinki and was approved by the ethics committee review board of Kyoto University Graduate School and Faculty of Medicine (approval number G531). The requirement to obtain informed consent was waived because of the retrospective design; however, general written informed consent was obtained.
: Not applicable.
: The authors declare that they have no competing interests.