HER2 Negative Breast Cancer: Invasive Breast Cancer…SYSTEMIC THERAPY FOR ER - AND/OR PR - POSITIVE RECURRENT OR STAGE IV (M1) DISEASE…HER2-Negative and Postmenopausal or Premenopausal Receiving Ovarian Ablation or Suppression…First-Line Therapy...Non-steroidal aromatase inhibitor (anastrozole, letrozole)...

Patients in the AI treatment group received anastrozole (1 mg), letrozole (2.5 mg), or exemestane (25 mg) once per day for 4 consecutive weeks (1 cycle). Patients in the fulvestrant treatment group received an intramuscular injection of fulvestrant (500 mg) on days 0, 14, 28, and every 28 days thereafter (1 cycle)....for both the whole cohort and the AI subgroup, the total survival of patients with ER+/PR+ breast cancer was longer than that of patients with ER+/PR− breast cancer, and the difference was statistically significant (P<0.001)....we found that PR status was an independent predictor of first-line endocrine therapy responses in hormone receptor-positive HER2 negative patients.