Duration of Adjuvant Aromatase-Inhibitor Therapy in Postmenopausal Breast Cancer

For postmenopausal women with hormone-receptor–positive breast cancer, the most effective duration for adjuvant therapy with an aromatase inhibitor remains unclear. In this prospective, phase 3 trial, we randomly assigned postmenopausal women with hormone-receptor–positive breast cancer who had received 5 years of adjuvant endocrine therapy to receive the aromatase inhibitor anastrozole for an additional 2 years (2-year group, receiving a total of 7 years) or an additional 5 years (5-year group, receiving a total of 10 years). The primary end point was disease-free survival...