Adding ultrasound screening to mammography brings benefits, risks

Adding a screening ultrasound examination to routine mammography reveals more breast cancers than mammography alone, according to results of a major new clinical trial. The trial, however, also found that adding an ultrasound exam also increases the rate of false positive findings and unnecessary biopsies.

Results of the clinical trial, conducted by the American College of Radiology Imaging Network (ACRIN) and analyzed by Brown University statisticians, appear in the May 14, 2008 issue of the Journal of the American Medical Association.

“The trial uncovered a significant trade-off with ultrasound screening,” said Jeffrey Blume, an associate professor in the Department of Community Health and the deputy director of the ACRIN Biostatistics and Data Management Center at Brown. “While supplemental ultrasound screening uncovers more breast cancers, it also substantially increases the risk of a false positive cancer finding and unnecessary biopsy.”

“The medical community may well decide that the screening benefit is offset by the increase in risk to women from a false positive finding,” Blume said. “However this study also shows that supplemental ultrasound may be beneficial in women at high risk of breast cancer who could not, or would not, otherwise undergo a magnetic resonance imaging scan. Women should consult their doctor for more information.”

A biostatistician and trial methodologist, Blume oversaw the statistical design of the ACRIN trial and led the analysis of the study, which enrolled 2,809 women in 21 clinical sites in the United States, Canada and Argentina. Participants were women at increased risk for breast cancer – women 25 years or older, women with dense breasts, women with a family history of breast cancer, and women who’d already had a breast biopsy.

The goal of the study was to determine whether the addition of a screening ultrasound to the current screening practice of mammography would reveal more cancers than mammography alone. Ultrasound screening uses high frequency sound waves to depict and detect tumors, while mammography – the current gold standard for breast cancer screening – uses low-dose X-ray.

During the first year of screening, mammography alone revealed breast cancers at a rate of 8 for every 1,000 women screened and resulted in 25 women for every 1,000 screened having an unnecessary biopsy due to a false positive exam. The combination of mammography and ultra-sound revealed breast cancers at a rate of 12 for every 1,000 women screened and resulted in 93 women for every 1,000 screened having an unnecessary biopsy due to a false positive exam.

So the ultrasound exam caught cancer in four additional women. But the exam also caused false positive findings in 68 additional women for every 1,000 screened – a four-fold increase.

“This false positive rate is significant,” Blume said. “And the combination of screening exams, both mammography and ultrasound, still missed one out of every five cancers. So the trial shows that ultrasound is not a silver bullet for breast cancer screening.”

Source: Brown University

Related stories:

Symptom screening plus a simple blood test improves early detection of ovarian cancer
Women's reports of persistent, recent-onset symptoms linked to ovarian cancer – abdominal or pelvic pain, difficulty eating or feeling full quickly and abdominal bloating – when combined with the CA125 blood test may improve the early detection of ovarian cancer by 20 percent, according to new findings by researchers at Fred Hutchinson Cancer Research Center published online in CANCER.

Kylie's breast cancer triggered a surge of over 30 percent in breast imaging of low-risk women
Kylie's breast cancer triggered a surge of over 30 per cent in breast imaging of low risk women, says new University of Melbourne study.
Adding ultrasound to mammography may improve breast cancer detection in high-risk women
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.
Study finds patients with complex fibroadenomas can avoid surgery
Complex fibroadenomas have a low incidence of malignancy, so women with this condition can be more conservatively treated and avoid surgical biopsy, according to a new study by a team of researchers from the Hadassah-Hebrew University Medical Center in Jerusalem.
Breast MRI spots other cancers, may alter treatment plan
In about 20 percent of women with breast cancer who plan to undergo a lumpectomy, breast magnetic resonance imaging reveals important diagnostic information that alters their treatment plan, University of Florida surgeons reported today (Dec. 5).
Research finds similarities in dog, human breast cancer pre-malignant lesions
Pre-malignant mammary lesions in dogs and humans display many of the same characteristics, a discovery that could lead to better understanding of breast cancer progression and prevention for people and pets, said a Purdue University scientist from the School of Veterinary Medicine.
Ultrasound plus mammography finds more cancers, but increases false positives
Adding ultrasound to mammography finds more cancers than mammography alone, but also substantially increases the number of false positives, according to first-year results from a three-year study of the two tests.
Screening MRI allows detection of more breast cancers in high-risk women
Magnetic resonance imaging (MRI) enables radiologists to accurately identify tumors missed by mammography and ultrasound, according to a multicenter study comparing the three screening methods in women at high-risk for breast cancer. The findings of the study appear in the August issue of the journal Radiology.

News discussion:

Medicine & Health news