Trial of Perioperative Endocrine Therapy - Individualising Care

To determine whether perioperative endocrine therapy with an aromatase inhibitor (AI) followed by standard adjuvant therapy improves outcome compared with standard adjuvant therapy alone in postmenopausal women with hormone receptor positive breast cancer. To determine whether the proliferation marker Ki67 as measured by immunohistochemistry (IHC) in the excised cancer around 2 weeks after starting AI therapy will predict for time to recurrence (TTR) in the individual patient more effectively than the pre-treatment Ki67 value. To determine whether molecular profiling 2 weeks after starting endocrine therapy predicts for long-term outcome in postmenopausal women with hormone receptor positive breast cancer better than at diagnosis.