Received: 23 July 2020
Accepted: 29 October 2020
First Online: 11 November 2020
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Institutional Review Board of Fukushima Medical University (Number 2399). This study is the retrospective study. Patients were not required to give informed consent because this study used anonymous clinical data obtained after each patient had agreed to medical activities by written consent. For full disclosure, the details of this study are published on the home page of Fukushima Medical University.
: Not applicable.
: The authors declare that they have no competing interests.