Breast cancer screening: the evolving evidence

Breast cancer is a leading cause of cancer and death from cancer among women in the developed and developing world. Detecting and treating breast cancer earlier in its natural history improve prognosis and result in a reduction in breast cancer mortality. There have been eight population-based randomized controlled trials (RCTs) of mammography screening, which individually and collectively provide strong support for the efficacy of breast cancer screening. The evaluation of modern service screening also has shown that modern breast cancer screening is contributing to reductions in breast cancer mortality at a rate as good as or better than that observed in the RCTs. In the last decade, different interpretations of the evidence from the RCTs and observational studies have resulted in different screening guidelines and contentious academic debates over the balance of benefits and potential harms from breast cancer screening. In this paper, the historic and recent evidence supporting the value of breast cancer screening will be described, along with the underpinnings of the current debate over the relative and absolute benefit of regular mammography screening.