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Article History

Received: 13 October 2025

Accepted: 4 March 2026

First Online: 15 April 2026

Declarations

:

: This study was approved by the Kanagawa Cancer Center Clinical Ethics Review Committee (28 Epidemic-56) and was conducted in accordance with the Declaration of Helsinki and relevant ethical guidelines for clinical and epidemiological studies. Among the 212 patients enrolled in the JBCRG-16 (Neo-Lath) trial (UMIN000007576), 112 (52.8%) provided written informed consent to participate in an ancillary study involving serum analysis. Institutional review board approval was obtained from each participating site for both the original trial and the follow-up study, including the National Hospital Organization Osaka National Hospital (approval no. 2011-0017 on January 17, 2012/approval no. 2014 − 1015 on June 17, 2014). Informed consent was obtained from all patients at the beginning of the JBCRG-16 (Neo-Lath) trial.

: Consent for publication is not required as the submission does not include any images or information that may identify the person.

: Tatsuya Yoshida reports honoraria for lectures from AstraZeneka, Chugai Pharmaceutical, Daiichi Sankyo, Lilly Japan, Pfizer, and Taiho Pharmaceutical. Kosuke Kawaguchi reports research funds and/or honoraria from Chugai, Eli Lilly, Daiichi Sankyo, AstraZeneca, Kyowa Kirin, Eisai, MSD, and Takeda. Rikiya Nakamura reports honoraria from Chugai, AstraZeneca, Daiichi Sankyo, Nihon Kayaku, Eli Lilly, Exact Science, Medicone BD, and Kyowa Kirin. Shigenori E. Nagai reports honoraria from Eli Lilly, Pfizer, Chugai, Taiho, Eisai, MSD, Daiichi Sankyo, and AstraZeneca. Norikazu Masuda reports research funds from Chugai Pharmaceutical Co., Novartis, AstraZeneca, Daiichi Sankyo, Eisai, Eli-Lilly, Gilead Sciences, MSD, Ono-Pharma, and Pfizer unrelated to the submitted work, receiving honoraria as lecture fees from AstraZeneca, Chugai Pharmaceutical Co., Daiichi Sankyo, Eizai, Eli-Lilly, and Pfizer. Norikazu Masuda is a member of the board of directors of the Japan Breast Cancer Research Group Association (JBCRG) and served as its representative for four years from 2021 to 2025. Masakazu Toi reports research funds from Kansai Med Net, AFI Technology, Eisai, Astellas, Nippon Kayaku, Taiho, Sanwa Syurui, Shimadzu, Chugai, Pfizer, Yakult, Zene, AstraZeneca, and JBCRG unrelated to the submitted work; receiving consulting fees from Bertis, Eli Lilly, Daiichi Sankyo, honoraria from AstraZeneca, MSD, Eisai, Devicore Medical Japan, Kyowa-Kirin, Daiichi Sankyo, Eli Lilly, Nippon Kayaku, Taiho, Exact Science, Shimadzu, Chugai, Pfizer, Yakult, and Sysmex. Masakazu Toi is a chairman of the Japanese Breast Cancer Society for two years from 2022 to 2024 and a member of the board of directors of the JBCRG from 2007 to 2023 and KBCRN from 2015 to present. Tetsuro Sasada reports research funds from Taiho and Ajinomoto unrelated to the submitted work. The other authors declare that they have no potential conflicts of interest.