Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): An international, double-blind, randomised placebo-controlled trial

Abstract

Background Aromatase inhibitors eff ectively prevent breast cancer recurrence and development of new contralateral tumours in postmenopausal women. We assessed the effi cacy and safety of the aromatase inhibitor anastrozole for prevention of breast cancer in postmenopausal women who are at high risk of the disease. Methods Between Feb 2, 2003, and Jan 31, 2012, we recruited postmenopausal women aged 40-70 years from 18 countries into an international, double-blind, randomised placebo-controlled trial. To be eligible, women had to be at increased risk of breast cancer (judged on the basis of specifi c criteria). Eligible women were randomly assigned (1:1) by central computer allocation to rec..