HK and NK received collaborative research funding from Intuitive Surgical Sarl, Johnson and Johnson K.K., National Clinical Database, and Nipro corporation. NN received grants from Chugai, Daiichi Sankyo, Eisai, Mochida, Novartis, and Pfizer; and honoraria from Astra Zeneca, Chugai, Daiichi-Sankyo, Eli Lilly, MSD, and Pfizer. YS received honoraria from Astra Zeneca, Celltrion Healthcare Japan, Chugai, Daiichi Sankyo, Eisai, Eli Lily, Kyowa Kirin, MSD, Nippon Kayaku, Pfizer, and Sysmex. MM received honoraria from AstraZeneca, Chugai, Daiichi Sankyo, Eisai, Eli Lilly, MSD, Pfizer, and Taiho. M Nagahashi received honoraria from AstraZeneca, Chugai, Daiichi Sankyo, Denka, Eli Lilly, Esai, Kyowa-Kirin, MSD, Novartis, Pfizer, and Taiho. MY received consulting fees from Roche Japan and honoraria from Agilent Technologies, Chugai Pharma, Daiichi Sankyo, MSD, Ono Yakuhin, and Roche Japan; and participated a board of Daiichi Sankyo. MK received research grants from Advalife Science, GL Sciences, Guardant Health AMEA, Kyowa Kirin, Nippon Kayaku, and Shimadzu; participated in the clinical trials of Eli Lilly, Japan Breast Cancer Research Group, Merck, and Roche; and received lecture fees from Chugai, Daiichi Sankyo, Devicor Medical Japan, Eisai, Guardant Health AMEA, Pfizer Japan, and Taiho. Sasada received grants from Chugai, Daiichi Sankyo, Eli Lilly, Gilead Sciences, and Nipro. S Saji received grants from Chugai, Daiichi Sankyo, Eisai, Taiho, and Takeda; participated in clinical trials of Astra Zeneca, Chugai, Daiichi Sankyo, Eli Lilly, Gilead, MSD, and Sanofi; received honoraria from Astra Zeneca, Chugai, Daiichi Sankyo, Eisai, Eli Lilly, Exact Sciences, Gilead, Kyowa Kirin, MSD, Nipponkayaku, Novartis, Ono, Pfizer, Taiho, and Takeda; participated a board of Astra Zeneca, Chugai/Roche, Daiichi Sankyo, Eli Lilly, Kyowa Kirin, MSD, and Pfizer; and was an executive board member of Breast International Group, Japan Breast Cancer Research Group, Japanese Breast Cancer Society, and Japanese Society of Medical Oncology. These conflicts of interest are outside the submitted work.

This article does not contain any studies with animals performed by any of the authors. All procedures performed in studies involving human participants 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.