Received: 19 March 2021
Accepted: 14 December 2021
First Online: 14 January 2022
: The retrospective study protocol was approved by the National Cancer Center Research Ethics Review Committee (Tokyo, Japan; NCCH 2014-092), which waived the requirement for informed consent. Patients are able to opt-out of the research use of their data at the hospital’s website. All research was conducted in accordance with the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.