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Article History

Received: 28 January 2026

Accepted: 1 June 2026

First Online: 12 June 2026

Declarations

:

: Grants or contracts from any entity—S Sasada: Chugai, Daiichi-Sankyo, Eli Lilly, Gilead Sciences, and Nipro; HK: Amgen, National Clinical Database, and Pfizer. MK: Advalife Science, Chugai/Roche, Eli Lilly, Fujiwara Memorial Foundation, JBCRG, and Merck; S Saji: AstraZeneca, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Gilead Sciences, MSD, Sanofi, Taiho, and Takeda; NN: Boehringer Ingelheim, Chugai, Daiichi-Sankyo, Eisai, and Novartis; NT: Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Kyowa Kirin, and Taiho. Consulting fees—HK: EPS corporation; MY: Roche. Payment or honoraria for lectures—S Sasada: Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Kyowa Kirin; HK: Novartis; MK: AstraZeneca, Chugai, Daiichi-Sankyo, Devicor Medical, Eisai, Guardant Health AMEA, and Pfizer; S Saji: AstraZeneca, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Exact Sciences, Gilead Sciences, Kyowa Kirin, MSD, Nippon Kayaku, Novartis, Ono, Pfizer, Taiho, and Takeda; MN: AstraZeneca, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Exact Sciences, Kyowa Kirin, MSD, Pfizer, and Taiho; MM: AstraZeneca, Chugai, Daiichi-Sankyo, Eli Lilly, Exact Sciences, Gilead Sciences, MSD, and Pfizer; MY: Agilent Technologies, Chugai, Daiichi-Sankyo, MSD, Ono, and Roche. YS: AstraZeneca, Chugai, Daiichi-Sankyo, Eisai, Eli Lily, Kyowa Kirin, MSD, Nippon Kayaku, Pfizer, and Sysmex; NN: AstraZeneca, Chugai, Daiichi-Sankyo, Eli Lilly, MSD, and Pfizer; NT: AstraZeneca, Boehringer Ingelheim, Chugai, Daiichi-Sankyo, Eisai, Eli Lilly, Kyowa Kirin, MSD, Pfizer, and Takeda. Participation on a Data Safety Monitoring Board or Advisory Board—T Konishi: Health Insurance Claims Review and Reimbursement Services. S Saji: AstraZeneca, Chugai/Roche, Daiichi-Sankyo, Eli Lilly, Kyowa Kirin, MSD, and Pfizer; MY: Daiichi-Sankyo. Leadership or fiduciary role—S Saji: JBCRG, and JBCS. Stock or stock options— S Sasada: Daiichi-Sankyo.Other financial or non-financial interests—HK: affiliation to the social collaboration department at the University of Tokyo supported by the National Clinical Database, Intuitive Surgical Sarl, Johnson and Johnson, and Nipro; NK: employed as a specially appointed academic staff member with funding provided by National Clinical Database. NT: director of the Japanese Breast Cancer Society, and chairperson of the Registration Database Committee of the Japanese Breast Cancer Society.

: This article does not contain any animal studies conducted by any of the authors. All procedures involving human participants performed in this study were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

: Formal consent was not required for this study.