Combining 2D and 3D digital mammography enhances screening
Integrated 2-dimensional (2D) and 3-dimensional (3D) mammography improves the detection of breast cancer and reduces false-positive findings compared with conventional 2D screening alone, researchers have found.
Nevertheless, noted investigator Nehmat Houssami, MBBS, PhD, of the University of Sydney School of Public Health in Sydney, Australia, his group's results do not warrant an immediate change to breast-screening practice. “Instead, they show the urgent need for randomized controlled trials of integrated 2D and 3D versus 2D mammography,” asserted Houssami in a statement issued by The Lancet Oncology, the journal in which the study was published.
Although 3D mammography had been explored in a few relatively small studies, the new project is the first completed trial to report on the effectiveness of 3D screening in a large group of women attending population-based screening, according to the Lancet Oncology statement.
The prospective comparative study, known as STORM (Screening with Tomosynthesis OR standard Mammography), focused on asymptomatic women aged 48 years or older (median age 58 years) who attended population-based screening for breast cancer in Italy from Auust 2011 to June 2012. The STORM investigators performed screen-reading in two sequential phases: 2D only, and integrated 2D and 3D mammography.
Screening detected 59 breast cancers, including 52 invasive cancers, in 57 of 7,292 women. Both 2D and integrated 2D and 3D screening detected two-thirds (39, or 66%) of the cancers.The remaining 33% (20 cancers), however, were not spotted when the 2D screen alone was used; they only came to light upon the application of integrated 2D and 3D screening. This translated to detection rates of 5.3 cancers per 1,000 screens for 2D only, and 8.1 cancers per 1,000 screens for integrated 2D and 3D screening.
A total of 141 false-positive findings occurred with 2D screening only, and 73 with integrated 2D and 3D screening. However, 181 false-positives occurred at both screen readings, indicating that such results are still an important issue that needs to be accounted for in breast screening.