Combination of Mammogram-Ultrasound Screening Increases Invasive Breast Cancer Detection Rates in Higher-Risk Women

CINCINNATI—Adding a screening ultrasound or magnetic resonance imaging (MRI) to annual mammography in women with an increased risk of breast cancer and dense breast tissue resulted in a higher rate of breast cancer detection, according to a new study conducted in a population of more than 2,600 women.

The local arm of this American College of Radiology Network study was led by Mary Mahoney, MD, a professor of radiology at the University of Cincinnati (UC) College of Medicine. The national team reports its findings in the April 4, 2012, issue of the Journal of the American Medical Association.

For this study, researchers set out to determine whether annual screening ultrasound would result in better breast cancer detection among a higher-risk population.

A total of 2,662 women were recruited at 22 centers across the U.S., including 157 women at the UC Health Barrett Cancer Center. Each trial participant had routine screening mammograms and physician-performed ultrasound screenings annually for three years. A subsegment of the study population (612 women) then underwent an MRI breast cancer screening.
 
Researchers then analyzed the resulting 7,473 mammogram and ultrasound screenings, 110 of whom had 111 breast cancer events. Fifty-nine cancers (53 percent) were detected by mammography, including 33 (30 percent) that were detected by mammography only; 32 (29 percent) by ultrasound only; and nine (8 percent) by MRI only after both mammography and ultrasound screens failed to detect cancer. Eleven cancers (10 percent) were not detected by any imaging screening exam. A total of 16 of 612 women (2.6 percent) in the MRI sub-study were diagnosed with breast cancer.

"Mammography is a strong tool that has saved the lives of many women, but the technology has been shown to miss about half the cancers present in women with dense breast tissue,” explains Mahoney, who also serves as director of breast imaging for UC Health University Hospital. "Our study and others support adding MRI as part of regular breast cancer screening for women who fall into this category (i.e., high-risk women with dense breast tissue) as a means of more accurately diagnosing cancer in earlier, more treatable stages.”

Previous single-center studies and smaller multi-center trials have shown that supplemental screening breast ultrasound increases detection of node-negative (localized) invasive breast cancer in women with dense breast tissue.

"What makes this study so powerful is the scope of data collection (three years) and population size (2,662 women). As radiologists, this scientifically tested data helps clearly guide our day-to-day clinical practice decisions so that we can pair our patient’s individual circumstances with the screening approach most likely to find her cancer, without unnecessarily invasive procedures or added health care costs,” explains Mahoney.

Study authors stress that while supplemental ultrasound and MRI screening detect more cancers, the imaging tests are not meant to replace an annual mammogram.

Funding for this research was provided by a partnership between the Avon Foundation and the National Cancer Institute (NCI). ACRIN is a clinical trials research organization and member of NCI’s Cooperative Group Program.