Supplementing screening mammography with whole-breast ultrasound may not be worth the trouble, according to new findings published in JAMA Internal Medicine.
The study’s authors noted that many researchers have advocated for whole-breast ultrasound and mammography to be used together when screening women with dense breast tissue. Others, however, have found the evidence is unclear.
“Accurate information on the effectiveness of screening ultrasonography is needed to provide guidance on whether widespread use of screening breast ultrasonography with screening mammography would be a beneficial strategy,” wrote Janie M. Lee, MD, MSc, department of radiology at the University of Washington in Seattle, and colleagues.
Lee et al. explored data from more than 6,000 examinations that included both screening mammography and whole-breast ultrasound. Women receiving both mammography and ultrasound, as opposed to just mammography alone, were more likely to be younger than 50 years old, white, have a family history of breast cancer, have dense breast tissue and have high Breast Cancer Surveillance Consortium five-year risk scores.
While mammography alone had a cancer detection rate (CDR) of 5.5 per 1,000 screens and an interval cancer rate of 1.5 per 1,000 screens, mammography and ultrasound had a CDR of 5.4 and an interval cancer rate of 1.9. Also, mammography and ultrasound together had a much higher false-positive biopsy rate (52 vs 22.2 per 1,000 screens) and a “significantly lower” positive predictive value of biopsy recommendation (9.5 percent vs 21.4 percent).
Lee and colleagues noted that prior researchers have observed “significant increases in incremental cancer detection rate” after supplementing screening mammography with ultrasound, but that wasn’t the case for this study. Another finding that stood out to the team was that 25.7 percent of the women receiving such screening didn’t have dense breasts.
Overall, the authors found that the benefits of supplemental ultrasound just might not outweigh the potential harms.
“Our observational cohort study of ultrasonography screening in women across a range of breast cancer risk found modest, nonsignificant benefits and rates of screening harms that were high and consistent with prior reports,” the authors wrote. “To apply supplemental ultrasonography screening with greater effectiveness, we suggest that additional efforts are needed to more accurately identify women who will benefit from supplemental screening. We also suggest that development is required of the capacity to deliver high-quality supplemental screening, as well as new interventions to reduce the frequency of screening-related harms.”