Improved breast cancer screening for women and society: A radiological approach

Breast cancer is the most common cancer in women, and early detection by mammographic screening is demonstrated to reduce mortality from the disease. BreastScreen Norway offers women aged 50-69 biennial mammographic screening. The overall aim of this thesis was to investigate ways to improve early detection of breast cancers in BreastScreen Norway and included analyses of screening techniques and screen-readers’ performance. A prospective study compared screening with a new mammographic technique, digital breast tomosynthesis, with standard digital mammography. A 50% increase in cancer detection at screening was observed in women screened with tomosynthesis, with no reduction in interval cancer. Cancers detected by tomosynthesis were mainly smaller and less aggressive compared with those detected by standard digital mammography. A retrospective, consensus based and fully informed review of mammograms from diagnosis and prior screening from women diagnosed with screen-detected or interval cancer indicated a potential for earlier diagnosis in a proportion of the cases. Analyses of the characteristics of these cancers may contribute to a reduction of cancers missed at screening