Screening ultrasound performs similarly after DBT, digital mammography

Screening ultrasound (US) resulted in similar cancer detection rates when performed after digital mammography (DM) and digital breast tomosynthesis (DBT), according to a new study published in the American Journal of Roentgenology.

DBT has gained popularity due to its improved detection of breast cancer in women with dense breasts, but a majority of research on screening US has focused on DM-based results, the researchers noted.

In their study published Sept. 24, Elizabeth H. Dibble, and colleagues analyzed more than 3,000 breast US exams performed across two breast imaging practices. They found “no significant difference” between screening US after DM versus after DBT.

“These findings suggest that patients who have undergone screening mammography with DBT maintain a similar benefit of detecting mammographically occult cancers on screening US compared with patients who have undergone screening mammography with DM,” Dibble, with Rhode Island Hospital’s Department of Diagnostic Imaging in Providence, and colleagues wrote.

More than 30 states have enacted laws mandating facilities inform women about breast density. However, as the authors pointed out, many experts have expressed concerns that the use of DBT has spiked despite relevant clinical evidence.

Industry organization have also disagreed about DBT’s role in screening. In fact, screening guidelines from the U.S. Preventative Services Task Force and American Cancer Society haven’t given the green light to DBT for routine screening due to insufficient evidence. But, the American Society of Breast Surgeons and American College of Radiology have each come out in support of DBT for mammography screening.

After retrospectively reviewing 1,434 breast US exams performed after DM and 1,668 completed following DBT, the cancer detection rate was 3.5 per 1,000 women and 3.0 per 1,000 women, respectively. Of the 36 biopsies or aspirations after DM, six were malignant and 30 were benign. For the 82 biopsies performed after DBT, 11 were malignant and 71 benign.

“No evidence was found of a difference in additional cancer detection rate with screening US after DM versus after DBT,” the authors wrote. “Knowing that the cancer yield of screening US is similar after DBT versus DM may help inform clinical practice, because questions abound about whether DBT is sufficient screening for women with dense breast tissue."