Footnotes

• Contributors TS and TKaj contributed equally to the conception and design of the study, collection and analysis of the study data, interpretation and drafting of the manuscript. MM and TKat contributed to the collection and analysis of research data, and critical revision of the manuscript for important intellectual content.

• Funding This research was supported by a grant from the Osaka Cancer Society in 2021.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.

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