Digital Mammography Increases Breast Cancer Detection Rates

The shift from film to digital mammography (DM) has increased the detection rate of breast cancer in the United Kingdom by 14%, without increasing the recall rate, according to a new study.

Researchers at the University of Oxford (United Kingdom), St. George’s University Hospital (St. Georges; London, United Kingdom), and Public Health England (London, United Kingdom) conducted a retrospective analysis of prospectively collected annual breast cancer screening data from 2009 to 2016 to measure the impact of changing from screen-film mammography to DM. In all, 11.3 million screening episodes were evaluated in women aged 45–70 years.

The results revealed that the overall cancer detection rate was 14% greater with DM, with substantially higher detection of grade 1 and grade 2 early-stage cancers, but not grade 3 invasive cancers. At first screening exams for women aged 45-52, DM increased the overall detection rate by 19%. Importantly, the higher sensitivity of DM did not increase the recall rate, the rate at which women are called back for additional screening based on suspicious results. In addition, DM significantly increased the detection of ductal carcinoma in situ (DCIS) at both first screens and subsequent screens. The study was published on December 11, 2018, in Radiology.

“Image quality with digital mammography is improved over that of screen film mammography. In particular, digital mammography provides the ability to visualize calcifications and see through denser tissue, and it allows the reader to adjust the image,” said study co-author radiologist Rosalind M. Given-Wilson, MBBS, of St. Georges. “This improvement happened in the absence of other changes in the English screening program, such as a change in recall rate or introduction of computer-aided detection, so we can be clear that the increased rate of detection is due to the change in technology.”

DM screening now also includes digital breast tomosynthesis (DBT), which can increase breast cancer detection rates even further. DBT mammograms use low dose x-rays to create a three-dimensional (3D) image of the breast, which can then be viewed the in narrow slices, similar to CT scans. While in conventional 2D mammography overlapping tissues can mask suspicious areas, 3D images eliminate the overlap, making abnormalities easier to recognize. It is estimated that 3D DBT will replace conventional DM within ten years.

Related Links:
University of Oxford
St. George’s University Hospital
Public Health England