The extent and stage of breast cancer at initial presentation determines treatment options and prognosis. Pre-operative disease extent is determined by mammography and image guided biopsy, although magnetic resonance imaging (MRI) may show further multifocal or multicentric disease. Histological assessment will give tumour size, type, grade, hormone receptor status and the presence of vascular invasion; however, a variety of imaging techniques can contribute to this information and perhaps give an in vivo functional assessment of tumour physiology. Lymph node involvement has been shown to have important prognostic status and is assessed by surgery or sentinel node biopsy. Ultrasound, MRI and nuclear medicine techniques, including positron emission tomography (PET), give variable results in the assessment of the axilla. Clinical assessment of tumour response in the neo-adjuvant setting is unreliable and imaging can more accurately measure tumour size and residual disease.

The contribution of mammography, ultrasound and MRI will be discussed together with a review of the potential contribution of the less commonly used nuclear medicine techniques and PET. The functional imaging techniques are being explored and may be used in the future to tailor patient management, particularly in the use of chemotherapy.