Efficacy of Anastrozole and Fulvestrant in Patients With ER Positive, HER2 Negative, Operable Breast Cancer

Overview

RATIONALE: Estrogen can cause the growth of breast cancer cells. Hormone therapy using anastrozole or fulvestrant may fight breast cancer by lowering the amount of estrogen the body makes or by blocking the use of estrogen by the tumor cells. Giving hormone therapy before surgery may be an effective treatment for breast cancer. It is not yet known whether anastrozole is more effective than fulvestrant when given before surgery in treating women with breast cancer. PURPOSE: This randomized phase II trial is studying anastrozole to see how well it works compared with fulvestrant in treating postmenopausal women with stage II or stage III breast cancer that can be removed by surgery.

OBJECTIVES: Primary * To compare the clinical response rates (complete and partial responses) at 6 months in postmenopausal women with operable stage II or III breast cancer treated with neoadjuvant anastrozole vs fulvestrant. Secondary * To compare the breast surgery conservation rate in patients treated with these drugs. * To correlate imaging findings by mammography, ultrasonography, and MRI with histological and clinical response in these patients and with sensitivity profile to these drugs. * To compare histological response in patients treated with these drugs. * To define criteria appropriate for neoadjuvant hormonal therapy. * To correlate baseline molecular characteristics and modifications during treatment with response in these patients. * To compare the tolerability of these drugs in these patients. * To compare the serum proteomic profile of patients treated with these drugs. * To correlate 3-year event-free and overall survival rates with clinical and histological response in these patients. OUTLINE: This is a multicenter study. Patients are randomized to 1 of 2 treatment arms. * Arm I: Patients receive oral anastrozole once daily for 4-6 months in the absence of clinical progression. * Arm II: Patients receive fulvestrant intramuscularly on days 1, 15, and 29 in the first month and then every 28 days in each subsequent month. Treatment continues for 4-6 months in the absence of clinical progression. Patients in both arms then undergo surgery and radiotherapy according to institutional guidelines. Patients then receive adjuvant hormonal therapy for at least 5 years. After completion of study therapy, patients are followed periodically for up to 3 years.