Text and Data Mining valid from 2020-02-08
Received: 30 October 2019
Accepted: 2 February 2020
First Online: 8 February 2020
Compliance with ethical standards
: This manuscript has not been published or presented elsewhere in part or in entirety and is not under consideration by another journal. The authors declare that they have no conflict of interest.
: This study was approved by the Ethics Committee of the National Hospital Organization of Kure Medical Center and Chugoku Cancer Center (Approval number 28-70) and is registered in the University Hospital Medical Information Network (UMIN000034966). All patients received a detailed explanation of the study from the primary physician, and written informed consent was obtained prior to enrollment.