FDA Panel OKs Ultrasound to Screen Dense Breasts

An FDA advisory panel unanimously voted in favor of an automated ultrasound device for breast cancer screening after a negative mammogram in women with dense breasts.

But in Wednesday's 13-0 vote, the Radiological Devices Advisory Panel recommended that the expanded indication include a restriction that the device be used only for such women who have not had a prior breast intervention, such as needle biopsy or breast cancer treatment.

The somo-v Automated Breast Ultrasound System (ABUS) is currently FDA approved as an adjunct to mammography in diagnosing breast cancer but not for screening.

The automated aspect of the technology would be helpful in the clinic for screening, Kristin Byrne, MD, chief of breast imaging at Lenox Hill Hospital in New York City, commented in an email to ABC News and MedPage Today.

"The automated image acquisition can help produce consistent results, allowing comparison between prior ultrasound exams in order to detect an interval change," she explained. "Handheld ultrasound is technologist-dependent, and images vary between different technologists making comparison more difficult."

Roughly 40% of women have dense breasts, which is associated with a four- to six-fold greater breast cancer risk, according to device manufacturer U-Systems in Sunnyvale, Calif.

The company and FDA reviewers emphasized that the automated breast ultrasound device is not intended to be used as a replacement for diagnostic mammography or diagnostic handheld ultrasound.

The advisory committee's decisions revolved around results from a pivotal study comparing how many breast cancers interpreting physicians found with an ultrasound scan added as a second screen after a negative mammogram versus mammogram alone in women with more than 50% parenchymal density (BI-RADS composition density 3 or 4).

The 200 asymptomatic cases had been drawn from a prospective multicenter registry in which women had both exams as part of their annual routine screening and cancers found were confirmed by pathology.

In that study, the addition of automated breast ultrasound screening boosted cancer detection with an area under the curve of 0.75 compared with 0.60 for mammography alone (P<0.001).

Accuracy improved as well, with sensitivity rising from 38.5% with mammography alone to 62.4% with the addition of breast ultrasound (P<0.001). Specificity did not significantly change and was 76.2% with the combination.

Adding automated breast ultrasound screening boosted the true positive rate by about 30% and the false positive rate by about 4%. The positive predictive value and negative predictive value were significantly greater with the combination as well.

For dense-breasted women at elevated cancer risk, a separate study by the American College of Radiology Imaging Network (ACRIN) showed that adding ultrasound to mammography in annual screening boosted breast cancer detection but also boosted the number of false positives.