That means for every woman screened, mammography alone will find 7.6 cancers, mammography plus ultrasound will detect 11.8 cancers, and three cancers will be missed altogether, the researchers said.
The study found that ultrasound was a good complementary screening tool for mammography, because it found cancers that mammography might miss.
"Ultrasound performs best in cases for which mammography performs weakest, i.e., in breast areas with dense fibroglandular tissue," Dr. Christiane Kuhl, with the Department of Radiology at the University of Bonn in Germany, wrote in an accompanying editorial in the journal. Kuhl also noted that the drawbacks to ultrasound include the frequency of false-positives, the cost of the test, and a lack of evidence that the test affects mortality.
Berg noted that there aren't currently enough physicians or ultrasound technicians trained for ultrasound to be a viable, widely used screening tool right now, even just for high-risk women.
"On average, physicians can only perform three to five ultrasounds per hour," said Berg, compared to as many as 50 mammograms in an hour, according to the editorial.
Dr. Julia Smith, director of the Lynne Cohen Breast Cancer Preventative Care Program at the New York University Cancer Institute and Bellevue Hospital in New York City, said, "I already do ultrasounds on women at risk. As a complementary test, ultrasound can be a very useful test. Also, we know it's relatively inexpensive and safe."
Magnetic resonance imaging (MRI) may be more effective than either mammography or ultrasound, and it's fast becoming a popular tool for breast cancer screening, but, Smith said, the cost of MRI is prohibitive.
Given limited health-care resources,
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