FDA Approves First Ultrasound Tool for Dense Breasts

Nick Mulcahy

September 18, 2012

September 18, 2012 — The US Food and Drug Administration (FDA) today approved the first ultrasound device for use in combination with mammography in women with dense breast tissue.

The device, known as the somo-v Automated Breast Ultrasound System (ABUS; U-Systems Inc, Sunnyvale, California), provides clinicians with an additional resource in screening women with dense breasts. The indication is limited to use in women who have a negative mammogram and no symptoms of breast cancer.

Mammograms of dense breasts can be difficult to interpret, the FDA points out in its announcement of the approval.

"A physician may recommend additional screening using ultrasound, for women with dense breast tissue and a negative mammogram," said Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostic Device Evaluation and Safety at the FDA's Center for Devices and Radiological Health. "The somo-v ABUS is a safe and effective breast ultrasound tool when such screening is recommended."

About 40% of women undergoing screening mammography have dense breasts, according to National Cancer Institute estimates. These women have an increased risk for breast cancer, with detection usually at a more advanced and difficult-to-treat stage, the FDA said.

In April, an expert advisory committee of the FDA voted unanimously to recommend the expanded use of ABUS as a screening tool for women with dense breast tissue.

However, as reported by Medscape Medical News, some of the panel members had concerns about ABUS because of its automated nature. In contrast to handheld ultrasound, medical specialists who operate an automated ultrasound do not have to be imaging experts, Robert Faulk, MD, from Medical Imaging Consultants in Omaha, Nebraska, noted during the meeting. "For instance, obstetricians and gynecologists could do ABUS and interpret the results themselves, along with mammography findings," Dr. Faulk said. "That could have a deleterious effect on healthcare for many women," he added.

"ABUS as a screening tool could potentially be applied to 40 million women in the United States [with dense breasts], and if it were used by nonimaging specialists, the false-positive rates could go through the ceiling," said Daniel Kopans, MD, from Harvard Medical School in Boston, Massachusetts. Dr. Kopans commented that postmarket surveys of the false-positive rate from ABUS could provide important data on the effect of its use as a screening tool in women with dense breasts.

Dense breasts have a high amount of connective and fibroglandular tissue compared with less-dense breasts, which have a high amount of fatty tissue, the FDA explained.

Fibroglandular breast tissue and tumors both appear as solid white areas on mammograms, which can complicate interpretation. Dense breast tissue may obscure smaller tumors, potentially delaying detection of breast cancer, according to the FDA.

Ultrasound imaging has been proven capable of detecting small masses in dense breasts.

A clinical study has shown a statistically significant increase in breast cancer detection when ABUS images were reviewed in conjunction with mammograms compared with mammograms alone. The study involved board-certified radiologists who reviewed mammograms alone or in conjunction with ABUS images for 200 women with dense breasts and negative mammograms.

As part of the approval, the FDA requires that the manufacturer train physicians and technologists using the ABUS device, and that the manufacturer provide each facility with a manual clearly defining system tests required for initial, periodic, and yearly quality control measures.

The ultrasound works via a transducer that directs high-frequency sound waves at the breast. The specially shaped transducer of the somo-v ABUS can automatically scan the entire breast in about 1 minute to produce several images for review, according to the FDA press materials.