Characteristics of 17,097 ER-positive and HER2-negative early BC patients who underwent upfront surgery for all patients, for patients <70 years or ≥70 years old, 70–74 years or 75–80 years or >80 years old, ≤40 years or 41–50 years old, and for breast lumpectomy or mastectomy are shown in Table 1 and Table 2. Here, ERBB2 is linked to breast cancer.