The study reviewed here adds to evidence showing that an annual breast MRI or breast ultrasound along with an annual mammogram improves breast cancer detection in women with dense breasts.
Dense breasts have less fatty tissue and more non-fatty tissue compared to breasts that aren't dense. Doctors can tell if breasts are dense by the way they look on a mammogram.
Other research has shown that dense breasts:
So an aggressive breast cancer screening plan that includes two or more types of imaging tests makes sense for women with particularly dense breasts.
In this study, 2,309 U.S., Canadian, and Argentinean women with dense breasts and a higher-than-average risk of breast cancer had both a screening mammogram and a breast ultrasound each year. In the study's third year, all the women were offered breast MRI; 612 women had one. The researchers figured out how many cancers not found by mammogram were found by breast ultrasound or MRI.
Ultrasound and mammogram together found 82% of the breast cancers. Mammogram alone found only 53% of the cancers.
Ultrasound was very good at identifying cancer: 94% of the areas that doctors thought were cancer based on ultrasound results turned out to be cancer. Still, because there were many areas that doctors weren't sure about, only 10% of all the biopsies that were done turned out to be cancer. This means there were many false positives. A false positive is an area that looks like a cancer, but turns out to be normal.
Using all three screening methods each year -- ultrasound, mammogram, and MRI -- found 85% of the breast cancers. Adding breast MRI to the screening plan caused even more biopsies to be done and most of these biopsies turned out to be negative, which means there were more false positives.
For women with dense breasts, a breast cancer screening plan that includes both an annual mammogram and an annual ultrasound is better at finding breast cancer than having only an annual mammogram. Compared to MRI, ultrasound is less expensive. Adding an annual MRI to the plan also increases screening effectiveness, but at a much higher cost than ultrasound.
It's important to know that including a breast ultrasound or breast MRI in screening plans for women with dense breasts will cause more false positives. Besides the concern about a possible breast cancer diagnosis, a false positive usually means more tests (including biopsies) and follow-up doctor visits. The process can be very stressful and upsetting.
Based on the results of this and other studies, it's a good idea to ask your doctor if you have dense breasts, as well as about your risk of breast cancer. If your breasts are dense or your risk of breast cancer is above average, an aggressive screening plan that includes breast ultrasounds and/or breast MRIs along with mammograms may make sense for you. Ask your doctor to explain the risks and benefits of having ultrasound or MRI in your screening plan. Together you can develop a screening plan that's right for you.
Visit the Breastcancer.org Screening and Testing section to learn more about screening tests.
CHICAGO (MedPage Today) -- Having an annual MRI or ultrasound in addition to mammography is beneficial for women with dense breasts who are at an elevated risk for breast cancer, researchers said here.
In a large multicenter trial, these more sensitive technologies increased cancer detection in this group, Wendie A. Berg, MD, PhD, of Johns Hopkins University, and colleagues reported at the Radiological Society of North America meeting here.
"Our recommendation is that women continue their annual mammography, and if they're high risk, they should have an additional MRI," Berg said. "If they can't tolerate an MRI, ultrasound is a reasonable alternative."
The findings come from an analysis of data from the ACRIN 6666 study, which involved 2,309 women at 21 centers in the U.S., Canada, and Argentina.
All of them had dense breasts and an elevated risk of breast cancer, and underwent a mammography and an ultrasound every year for three years.
In the third year, 612 women also had an MRI (1,215 were offered one, but many refused, most commonly citing claustrophobia or time constraints).
The researchers found that adding ultrasound to mammography increased cancer detection by an absolute rate of 29% -- rising from 53% with mammography alone to 82% with both screenings.
On ultrasound, 94% of the suspected lesions were found to be cancerous, and 96% of those were node-negative tumors with a median size of 10 mm.
Overall, there was a 34% absolute increase in invasive cancer detection, Berg said.
She said that adding the technology led to a 5% absolute increase in biopsies compared with mammography alone -- but she noted that only 10% of biopsies prompted by ultrasound ended up being malignant.
For patients who had an MRI in addition to a mammography and an ultrasound, the absolute increase in cancer detection was 56%, Berg said.
A total of 89% of cancers identified by MRI were invasive, leading to a 67% absolute increase in invasive cancer detection. MRI did, however, lead to an absolute 7.7% increase in biopsies.
She added that another downside to MRI was that it led to a higher rate of short-interval follow-up.
"If we choose to have supplemental screening with MRI, we need to recognize the high risk of false positives," Berg said.
She urged women at high risk to ask their physicians what their breast density is, and subsequently discuss their risk factors and screening methods with them.
"The study nicely showed a real advantage with ultrasound," said Joseph Tashjian, MD, of St. Paul Radiology in St. Paul, Minn. "It's not invasive, it's easy, it's not expensive, and it can be done in any setting."
"MRI had even better results, but it's more expensive and it includes administration of a contrast agent," he said. He added that insurance companies are less likely to cover MRI because of the cost and the previous lack of data on its efficacy.
"[Reimbursement for MRI] has always been a problem," he said, "but it has increased rather than gone away. Every time new guidelines come out, it's a reason for insurance companies to revisit their policies."
The ACRIN 6666 study was funded by the Avon Foundation and the National Cancer Institute.
Berg reported being a consultant for Naviscan.
A co-author reported relationships with General Electric, Konica Minolta Group, VuCOMP, Real Imaging, and Sectra AB.
Primary source: Radiological Society of North America Source reference: Berg WA, et al "Screening breast ultrasound as a supplement to mammography: Yield of annual screening in ACRIN 6666 American College of Radiology Imaging Network" RSNA 2009; Abstract VB31-04.
Breastcancer.org is a non-profit organization dedicated to providing information and community to those touched by this disease. Learn more about our commitment to providing complete, accurate, and private breast cancer information.
Breastcancer.org 7 East Lancaster Avenue, 3rd Floor Ardmore, PA 19003
©2011 Breastcancer.org - All rights reserved.
