Adding Ultrasound to Mammography May Improve Breast Cancer
Detection in High-Risk Women
CHICAGO The addition of an ultrasound examination to
mammography for women at high-risk of breast cancer resulted in
a higher rate of cancer detection, but also increased the number
of false-positive results, according to a study in the May 14
issue of JAMA.
Supplemental screening ultrasound has the potential of depicting
small, node-negative breast cancers (when there is no cancer in
the lymph nodes) not seen on mammography, according to
background information in the article.
Wendie A. Berg, M.D., Ph.D., of the American Radiology Services
Inc., Johns Hopkins Green Spring, Lutherville, Md., and
colleagues conducted a study to compare the diagnostic
effectiveness of screening breast mammography plus ultrasound
vs. mammography alone in women at increased risk of breast
cancer. The study included 2,809 women with dense breast tissue
who were randomized to undergo mammographic and ultrasonographic
examinations.
Forty participants (41 breast lesions) were diagnosed with
cancer: 8 suspicious on both ultrasound and mammography; 12 on
ultrasound alone; 12 on mammography alone; and 8 participants
(involving 9 breast lesions) on neither.
The diagnostic yield for mammography was 7.6 cancers per 1,000
women screened (20/2,637); 31 cancers were diagnosed in 2,637
participants by the combination of mammography plus ultrasound,
producing a yield of 11.8 per 1,000 women, and an increased
yield due to ultrasound of 4.2 per 1,000 over mammography alone
(or an additional 1.1 to 7.2 cancers per 1,000 high-risk women).
The diagnostic accuracy of mammography was 0.78; for ultrasound,
0.80; and for combined mammography plus ultrasound, 0.91. The
positive predictive value of biopsy recommendation after full
diagnostic workup was 19 of 84 for mammography (22.6 percent),
21 of 235 for ultrasound (8.9 percent), and 31 of 276 for
combined mammography plus ultrasound (11.2 percent).
The false-positive rate for mammography was 4.4 percent; for
ultrasound, 8.1 percent; and for combined mammography plus
ultrasound, 10.4 percent.
The detection benefit of a single screening ultrasound in women
at elevated risk of breast cancer is now well validated.
However, it comes with a substantial risk of false-positive
results (i.e., biopsy with benign results and/or short interval
follow-up). Our results should be interpreted in the context of
recent guidelines recommending annual magnetic resonance imaging
[MRI] in women at very high risk of breast cancer, the authors
conclude.
Source: JAMA
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