The shift from film to digital mammography increased the detection of breast cancer by 14% overall in the United Kingdom without increasing the recall rate, according to a study appearing in Radiology.
“Image quality with digital mammography is improved over that of screen film mammography,” said radiologist and study coauthor Rosalind M. Given-Wilson, MBBS, from St. Georges University Hospitals NHS Foundation Trust, London. “In particular, digital mammography provides the ability to visualize calcifications and see through denser tissue, and it allows the reader to adjust the image.”
Dr. Given-Wilson and colleagues assessed digital mammography’s impact on cancer detection using data from the 80 facilities of the English National Health Service Breast Cancer Screening Program. The huge trove of data combined with estimates of digital mammography usage enabled the researchers to measure the effect of digital mammography in 11.3 million screening exams in women between the ages of 45 and 70.
The overall cancer detection rate was 14% greater with digital mammography, with substantially higher detection of grade 1 and grade 2 invasive cancers.
At first screening exams for women aged 45 to 52, digital mammography increased the overall detection rate by 19%. Importantly, the higher sensitivity of digital mammography did not increase the recall rate.
Digital mammography increased the detection of some types of cancers more than others. For instance, digital mammography significantly increased the detection of ductal carcinoma in situ, or DCIS, at both first screens and subsequent screens.
While digital mammography improved detection of grade 1 and 2 cancers, the researchers found no improvement in the detection of grade 3 invasive cancers.
The researchers are looking at the radiological features of grade 3 cancers on digital mammography to see if optimizing the image for these lesions can aid detection. They are also studying the relationship between grade 3 cancers and subsequent interval cancers, or cancers that appear between screenings.