Received: 19 March 2021
Accepted: 6 May 2021
First Online: 17 May 2021
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the institutional review board of Yokohama City University Hospital (Approval Number: B200700100). The need for informed consent was waived by the institutional review boards because of the retrospective observational design of the study.
: Not applicable.
: The authors have disclosed that they do not have any potential competing interest.