By Will Boggs MD
NEW YORK (Reuters Health) - 27/6/2019
Digital breast tomosynthesis (DBT) is now the predominant mode of breast cancer screening in 41.8% of hospital referral regions, according to an analysis of Blue Cross Blue Shield claims.
"Tomosynthesis is rapidly becoming a mainstream screening modality," Dr. Ilana B. Richman of Yale School of Medicine, in New Haven, Connecticut, told Reuters Health by email. "It is important for physicians, particularly those in primary care and in women's health, to understand the technology (and) the evidence and to help patients navigate choices about what screening test might be right for them."
DBT appears to have lower recall rates and higher cancer-detection rates than two-dimensional mammography, but the trade-offs include higher costs and higher radiation doses with some machines.
The U.S. Preventive Services Task Force and the American Cancer Society say there is insufficient evidence to support the use of DBT for routine breast cancer screening, while the American College of Radiology supports it.
Dr. Richman's team used a database of Blue Cross Blue Shield claims to evaluate the adoption of DBT for breast cancer screening and to identify characteristics associated with its adoption.
In their study of over 9.6 million breast cancer screening examinations performed from 2015 through 2017, DBT use rose from 12.9% of screening examinations to 43.2% of screening examinations, the team reports in JAMA Internal Medicine, online June 24.
In early 2015, DBT was the predominant mode of breast-cancer screening (that is, used in >50% of screening examinations) in 4.6% of hospital referral regions. By the end of 2017, that number had climbed to 41.8%.
Hospital referral regions in the Northeast and Northwest tended to have more rapid growth and higher rates of DBT use at study end, whereas hospital referral regions in the Southeast had slower growth and lower overall rates of DBT use.
DDT was adopted more quickly in areas of the country with higher median household incomes and greater educational attainment and in areas with a larger percentage of white residents and a smaller black population.
"Whether this variation in DBT use affects health outcomes will ultimately depend on DBT's long-term effectiveness at reducing morbidity and mortality from breast cancer," the researchers conclude.
"Although early studies of DBT suggest that the technology may help radiologists distinguish normal areas from abnormal areas on a mammogram, we do not yet know how this might translate into improvements in women's health over the long term," Dr. Richman said. "There are ongoing studies, though, designed to answer this question."
"But this gap in evidence is important and perhaps has made some reluctant to switch to DBT," she said. "There are other barriers to adoption, including the costs of equipment for radiologists and costs to patients, as not all insurance plans cover DBT."
"False-positive screening is a major harm of mammography screening that is important to women, yet it remains unclear whether DBT improves clinical breast cancer outcomes compared with the use of screening mammography alone," write Dr. Joy Melnikow and Dr. Joshua J. Fenton of the University of California, Davis, in Sacramento, in a linked editorial. "Observational studies suggest increased sensitivity for breast cancer with the addition of DBT, but earlier detection of small breast cancers with overall favorable prognoses may not reduce breast cancer mortality."
"Five randomized clinical trials with a combined recruitment goal of 430,000 women are currently under way in Europe, the United Kingdom, and North America; within 2 to 5 years, they should provide more reliable information about diagnostic characteristics and comparative rates of interval cancers," they note.
"Effective, population-based implementation of evidence-based screening approaches coupled with programs that ensure access and adherence to effective treatment would likely have greater impact on breast cancer mortality and persistent racial disparities," their editorial concludes.
JAMA Intern Med 2019.