New imaging technique helps radiologists downgrade benign breast masses

Using optoacoustic (OA) imaging combined with conventional ultrasound (US) can help downgrade benign masses classified as BI-RADS 4A or 4B, according to a new study from Dutch researchers published in Radiology. This, the authors noted, could reduce the number of biopsies negative for cancer.

“The reported rates of US-guided biopsies with results positive for cancer are low, varying from 7.9 percent to 17 percent, which results in many biopsies of benign masses,” wrote lead author Gisela L. G. Menezes, MD, PhD, with the department of radiology and nuclear medicine at University Medical Center Utrecht in Utrecht, Netherlands, and colleagues. “In retrospect, many of these biopsies negative for cancer might be considered unnecessary because they result in increased emotional distress for patients and higher overall costs related to interventional procedures and short-interval follow-up imaging studies.

“Among the greatest challenges in US breast imaging are to improve the differentiation between benign and malignant lesions, to concurrently maximize sensitivity and specificity, to decrease false-positive findings while minimizing false-negative findings, and to decrease the number of biopsies negative for cancer.”

To see if OA/US technology could potentially help radiologists address this issue, the authors studied more than 200 breast masses evaluated with US alone and classified as BI-RADS 4A or 4B. The same masses were then evaluated a second time with OA/US.

“Regardless of the outcome at OA/US, a biopsy was performed after the OA/US examination solely on the basis of findings at conventional imaging (BI-RADS 4A or 4B),” the authors wrote. “All biopsied masses (and surgical specimens when available) underwent central pathologic review by an independent histopathologist. The central histopathologic diagnosis was considered the reference standard for OA/US comparison.” 

Overall, when evaluating with OA/US, more than 47 percent of benign masses classified as BI-RADS 4A and more than 11 percent of benign masses classified as BI-RADS 4B were “correctly downgraded” to BI-RADS 3 or BI-RADS 2.

Three masses, however, were “incorrectly downgraded.” These masses were malignant, and their classification should not have been changed. Menezes et al. reviewed these findings and found that the radiologists, not the technique, were to blame.

“From the three false-negative masses found in our study, two masses could have been prevented if OA/US signs suggestive of malignancy had been observed at OA/US,” the authors wrote. “Future analysis and studies performed to improve the scoring system used at OA/US may help to decrease the number of false-negative findings and may help us to unfold the full potential of this technology.”