The reduction in the incidence of contralateral breast cancer in women treated with adjuvant tamoxifen provided a model for prevention using endocrine agents. Oestrogen-receptor-positive cancer can be prevented with tamoxifen, but side effects limit its clinical utility, and the risk-benefit ratio is not sufficiently high to routinely recommend tamoxifen as a preventive agent. Agents being evaluated in prevention trials include raloxifene and the aromatase inhibitors; these are expected to be at least as effective as tamoxifen and to have fewer side effects. Core needle biopsy (providing histological information) and high-resolution breast ultrasound enhance preoperative assessment of breast cancer. Mammography remains the only screening test shown to reduce breast cancer deaths in randomised trials. Magnetic resonance imaging may have a role in screening women with inherited mutations of the breast cancer genes. Sentinel lymph node biopsy accurately assesses lymph node status and is associated with less morbidity than axillary dissection. Where the biopsy is negative (no histologic evidence of metastases), no further axillary treatment is necessary. Breast reconstruction after mastectomy can produce good cosmetic results, especially where autologous tissue is used. Myocutaneous flaps using latissimus dorsi or transverse rectus abdominus muscles are increasingly popular. Adjuvant trastuzumab therapy in patients whose tumours overexpress HER2 (growth factor receptor) can reduce recurrence rates and improve survival. Neoadjuvant endocrine therapy (as an initial treatment before surgery) is an underutilised treatment in postmenopausal women with oestrogen-receptor-positive large operable or locally advanced cancers. It makes more patients suitable for surgery and offers others the choice of breast conservation.