In this article the term 'neoadjuvant' is used to describe pre-operative treatment for 3 months or more for large (usually ≥ 3 cm) operable cancers before surgery. Clinical response and pathological response are important end-points. The term 'presurgical' refers to treatment of short duration (around 2 weeks) before surgery, sometimes referred to as a 'window of opportunity' study. This approach can be used for any size of cancer provided it can be core biopsied, and the endpoints are molecular markers. Traditional goals of neoadjuvant therapy include the following: • to improve survival; • to downstage so that inoperable cancers become operable or so that conservative surgery can replace mastectomy; • to identify short-term clinical or molecular markers of response to predict long-term outcome as a prelude to (or as a substitute for) adjuvant trials; • to predict outcome and plan further treatment in the individual patient; and • to identify the molecular mechanisms that underlie response and resistance to treatment. Short-term presurgical therapies can have similar aims with the proviso being that this treatment will not lead to downstaging and that clinical and pathological response rates are unrealistic end-points. Current evidence suggests that there is no survival benefit from neoadjuvant chemotherapy [1]. The question has not thus far been addressed in a large neoadjuvant endocrine therapy trial. Neoadjuvant chemotherapy has been shown to downstage and reduce the need for mastectomy in some but by no means all women [1]. The same is true for neoadjuvant endocrine therapy; about 40% of mastectomies can be avoided with preoperative aromatase inhibitor therapy [2].