Adding ultrasound to routine mammography improves cancer detection in dense breasts
The number of breast cancers detected in women with dense breasts was increased when those women with a normal mammogram underwent an additional breast ultrasound screening, according to data presented at the 2014 San Antonio Breast Cancer Symposium.
“Having dense breasts substantially increases a woman's risk of developing breast cancer,” said Jean M. Weigert, MD, FACR, a clinical radiologist and director of breast imaging at The Hospital of Central Connecticut in New Britain. “We found that among women with dense breasts, screening breast ultrasound detected a significant number of breast cancers not discovered by mammogram.”
In Connecticut, during 4 years of screening women with mammographically normal but dense breasts by breast ultrasound, the screening detected between three and four breast cancers per 1,000 women screened.
“This is important because it adds to the notion that breast cancer screening should be personalized, and that women with dense breasts should seriously consider adding a breast ultrasound to routine mammography,” continued Weigert.
On October 1, 2009, Connecticut became the first state to enact legislation mandating that patients undergoing mammography be informed of their breast density and that those with mammographically dense breasts be told that further screening may be beneficial.
Weigert performed a retrospective analysis of data from two radiology practices in Connecticut from October 2009 to December 2013. Each year, approximately 30,000 screening mammographies were conducted at these practices, and the number of screening dense breast ultrasounds was 2,706, 3,351, 4,128, and 3,331 in years 1 through 4, respectively. Breast ultrasound screens detected 11 breast cancers in year 1, 11 in year 2, 13 in year 3, and 11 in year 4.
Over the 4 years, the positive predictive value, which is the proportion of women with breast cancer among those with a positive breast ultrasound result, improved. It was 7.1% in year 1, 6.1% in year 2, 8.1% in year 3, and 17.2% in year 4.
“Over the 4 years, we have learned how to better identify those breast ultrasound abnormalities that may truly be cancer,” said Weigert. “The positive predictive value for mammography is [approximately] 20% to 30%. So we are getting close to this with breast ultrasound now that we are more experienced.”
Weigert declares no conflicts of interest.