Received: 24 May 2019
Accepted: 25 June 2020
First Online: 2 July 2020
Ethics approval and consent to participate
: All research was approved by the Ethics Committees of Kure Medical Center and Chugoku Cancer Center. All participants have provided written informed consent.
: Written informed consent for publication of identifying images or other personal or clinical details was obtained from all of the participants. A copy of the consent form is available for review by the Editor of this journal.
: The authors declare that they have no competing interests.