Funding for this research was provided by:
Japan Society for the Promotion of Science KAKENHI (JP20K17749)
Received: 21 February 2022
Accepted: 22 April 2022
First Online: 28 April 2022
: This study was approved by the Institutional Review Board of National Hospital Organization, Kure Medical Center and Chugoku Cancer Center (registration number: No. 2020–88) and the requirement for informed consent from each patient was waived because this study was a retrospective review of anonymized patient data. Patient consent was obtained by using informed consent documents with an opt-out process. The study was carried out in accordance to institutional guidelines which is established based on the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.