Chemotherapy plus endocrine therapy was associated with a clinically and statistically significant higher overall survival compared to endocrine therapy alone in women >50 years of age with RS >26 pT1 and pT2 N0M0 HR+/HER2‐breast cancer, suggesting that cytotoxic chemotherapy has an impact on reducing mortality that is independent of induction of premature ovarian failure. This evidence concerns the gene ERBB2 and breast cancer.