A new era in the diagnosis and treatment of breast cancer.

Randomized controlled mammography screening trials and the evaluation of service screening have unequivocally proven that regular mammography screening significantly reduces mortality from breast cancer. This evidence contradicts the theory of Fisher, claiming that breast cancer is a systemic disease from its inception and undermines the justification for systemic therapy in most screen-detected cancers, because they are still localized to the breast and can be cured by local treatment alone. When high quality mammographic screening is offered at regular intervals to 40- to 74- year-old women, over 50% of the invasive cancers will be detected in the size range of 1-14 mm, fewer than 20% will be axillary node positive, and only about 20% will be poorly differentiated. This predominance of early-stage disease has created a revolutionary new era for those involved in the diagnosis and treatment of patients with breast cancer.