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Article History

Received: 1 November 2019

Accepted: 14 April 2020

First Online: 21 April 2020

Ethics approval and consent to participate

: The study was approved by the ethics committees of all participating institutions based on biomedical research guidelines specified in the Declaration of Helsinki. Since the study was retrospective, informed consent was waived. Authors uploaded the information about this study and patients’ rights to the participating institutions’ websites. Ethics committees include Ethics Committee of Shizuoka Cancer Center (approval number: T28–40–28-3-3), Ethics Review Board of National Cancer Center Hospital (approval number: 2016–363), Aichi Cancer Center Institutional Review Board (approval number: 2016–1-256), and Institutional Review Board of The cancer Institute Hospital of Japanese Foundation for Cancer Research (approval number: 2016–1150). These approvals included all administrative permissions necessary to access and use the study administrative data.

: Not applicable. This is just the same as described above

: The authors declare that they have no competing interests.