We conducted this retrospective real‐world study in trastuzumab‐treated premenopausal early‐stage HR+/HER2+ breast cancer patients from multiple centers with the objectives of (1) identifying the real beneficiaries of OFS treatment in these patients and (2) exploring the clinicopathological factors affecting the prognosis of HR+/HER2+ patients. The gene discussed is ERBB2; the disease is breast cancer.