May 13 2008
Among women at high-risk of developing breast cancer, breast ultrasound combined with mammography may detect more cancers than mammography alone, according to results of a multicenter trial that included UT Southwestern Medical Center researchers.
Overall, 40 participants were diagnosed with breast cancer. Of those cases, a dozen lesions were suspicious only on ultrasound and eight were suspicious on both ultrasound and mammography.
The most recent findings, presented in the current issue of The Journal of the American Medical Association, are from the first round of screening in the American College of Radiology Imaging Network's ACRIN-6666 trial. More than 2,800 women at high risk of developing breast cancer participated. The median age of the participants was 55 years and more than half had a personal history of breast cancer.
Breast ultrasound is a noninvasive procedure that uses sound waves to make a picture of the tissues inside the breast. It has traditionally been used after mammography to evaluate possible abnormalities found at screening or on physical examination. Because of recently reported studies, breast cancer screening using ultrasound for high-risk women is beginning to gain traction.
Dr. W. Phil Evans, a study author and professor of radiology at the UT Southwestern Center for Breast Care, said ultrasound is attractive for supplemental screening because it is widely available, is well-tolerated by patients and involves no radiation. It's also less costly than magnetic resonance imaging.
However, adding a single ultrasound to mammography does increase the number of false positives," said Dr. Evans. "Whether or not the risk of false positives will diminish with subsequent rounds of the screening trial remains to be seen, but it's something we're tracking."
The trial compared the effectiveness of using ultrasound screening and mammography with mammography alone in detecting breast cancer. Potential candidates were excluded if they had signs or symptoms of breast cancer; had recent surgical or image-guided breast procedures; or if they had undergone MRI or tomosynthesis within 12 months, or mammography or whole breast ultrasound within 11 months. Women with breast implants and those who were pregnant, lactating or planning to become pregnant within two years of study entry were also excluded.
The results come on the heels of a recommendation by the American Cancer Society that annual breast MRI be used in addition to mammography for screening women at very high risk of breast cancer. The society's guidelines don't apply to the large number of women who are considered to be at intermediate or high risk for developing breast cancer but are not eligible for MRI.
The work was supported by the Avon Foundation and the National Cancer Institute.
Dr. Evans is on the scientific advisory board of Hologic, a diagnostic and medical imaging systems maker that's considered a leader in breast cancer diagnostics.
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