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Article History

Received: 13 December 2021

Accepted: 16 August 2022

First Online: 23 August 2022

Declarations

:

: This study was approved by the Ethics Committee of the Gunma Prefectural Cancer Center (approval # 405–31012). The study protocol was also approved by the Gunma University Hospital Clinical Research Review Board and the Ethics Review Committee of the National Hospital Organization Takasaki General Medical Center. All methods were performed in accordance with relevant guidelines and regulations (Declaration of Helsinki). Informed consent was not obtained from the study participants. According to the ethical guidelines for medical and health research involving human subjects in Japan, informed consent is not required for medical studies that use only medical records without using human samples, and the analysis is conducted with anonymized data. However, all patients were given the right to withdraw their consent for the use of the data using opt-out method on the Gunma Prefectural Cancer Center website in 2021. The Ethics Committees of Gunma Prefectural Cancer Center approved the opt-out method for obtaining participant consent for this study.

: Not applicable.

: The authors declare that they have no competing interests.