ESR1 and invasive ductal breast carcinoma: The clinical data between the two groups before and after matching the propensity score were analyzed, including age, body mass index (BMI), neo-adjuvant chemotherapy (NAC), breast conservation, invasive ductal carcinoma (IDC), histopathological grade, estrogen receptor (ER) status, progesterone receptor (PR) status, human epidermal growth factor receptor-2 (HER2) status, axillary lymph node (ALN) metastasis, chemotherapy, targeted therapy, endocrine therapy and radiotherapy (Table 3).