A statewide breast screening ultrasound program that recommended ultrasound for women with greater than 50 percent breast density was linked with the detection of an additional 3.4 cancers or high-risk lesions per 1,000 women screened, according to research presented April 18 at the annual meeting of the American Roentgen Ray Society (ARRS) in Washington, D.C.

The state of Connecticut pioneered breast density legislation; it requires breast density reporting on mammograms and recommends follow-up screening ultrasound for women with greater than 50 percent breast density.

Sarah Steenbergen, MD, from Yale New Haven Hospital in Woodbridge, Conn., and colleagues aimed to determine if the addition of screening ultrasound among dense-breasted women with normal mammograms improves cancer detection and cancer detection over time.

The researchers collected data from seven radiology practices in Connecticut, comprising a total of 132,847 screening mammograms and 19,745 screening ultrasound exams performed from Nov. 1, 2009, to Oct. 31, 2011.

A total of 87 percent of screening ultrasound exams were BI-RADS category 1 or 2, 8 percent were BI-RADS category 3, and 4 percent were BI-RADS category 4 or 5. Biopsy detected 67 breast cancers, and there was one false-negative ultrasound.

Steenbergen et al calculated a positive predictive value of 7.6 percent for screening breast ultrasound in women with mammographically normal but dense breasts. Negative predictive value, sensitivity and specificity were 99.94 percent, 98.5 percent and 95.6 percent, respectively.

Specificity and sensitivity improved from the first to second year, and suggests a learning curve that might increase the yield and decrease the number of benign biopsies, according to the researchers.

The ultrasound detection rate of 3.4 cancers per 1,000 women screened approaches the mammography rate of 4-5 cancers per 1,000 women screened.