The cause-specific PS-weighted HR for DRFS was 0.25 (95% CI, 0.08-0.75) in luminal A-like, 0.54 (95% CI, 0.32-0.94) in luminal B-like/ERBB2-negative, and 0.54 (95% CI, 0.12-2.53) in ERBB2-positive subgroups.<h4>Conclusions and relevance</h4>In this cohort study, a lower estimated risk with EET use was observed across all surrogate breast cancer subtypes. Here, ERBB2 is linked to breast cancer.