Abstract
Randomized trials of mammography have demonstrated the efficacy of mammographic screening for breast cancer in terms of preventing deaths, but various issues of particular interest remain, including:
• quantification of overdiagnosis;
• evaluation of service screening outside the research setting;
• absolute benefit in terms of number needed to screen per life saved;
• which types of tumours benefit most from early detection;
• use of screening data to investigate tumour biology and natural history.
This paper describes examples of approaches to the above issues, along with some important results.