Received: 2 April 2020
Accepted: 5 July 2020
First Online: 11 July 2020
Ethics approval and consent to participate
: This present study conforms to the Declaration of Helsinki and was approved by the Institutional Review Board (IRB) of the National Cancer Center Hospital (No: 2017–077).This is a retrospective study and no consent to participate to study was required.
: Not applicable.
: There are no competing interests.