Received: 25 August 2021
Accepted: 27 October 2021
First Online: 20 November 2021
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
: Patients treated at Shikoku Cancer Center, Ehime University Hospital, and Saiseikai Imabari Hospital consented in writing for the use of their anonymous data for research.
: The authors declare that they have no competing interests.