[Andrea Barnett Budin]

New (2012) ultrasound system approved for screening dense breasts: cancer can be difficult to detect in dense breasts screened with mammography, but ultrasound makes cancer easier to see

Source: Women's Health Advisor. 16.11 (Nov. 2012): p1.
Document Type: Article

Copyright : COPYRIGHT 2012 Belvoir Media Group, LLC http://www.belvoir.com


Full Text:
The first ultrasound device that has the potential to increase breast cancer detection in women with dense breasts has won approval as a screening tool for use in combination with standard mammography. The U.S. Food and Drug Administration (FDA) approved the device on September 18, 2012.


The somo-v Automated Breast Ultrasound System (ABUS) has been in limited use in select practice settings in the U.S. since 2005 as an adjunct to mammography.

The FDA approval makes it the only device authorized specifically for screening women with dense breasts who have no palpable lumps or any other signs of breast cancer, and whose mammograms are negative.


Dense breasts make cancer detection difficult

The National Cancer Institute estimates that about 40 percent of women have dense breasts--breasts that contain more milk-producing glands and connective tissue than they do fat. (The other 60 percent of women have breasts that contain 75 percent or more fatty tissue.) "Some recent studies suggest that increased breast density may increase the risk of breast cancer as much as four- to sixfold," says Kemi Babagbemi, MD, assistant professor of radiology at Weill Cornell Medical College. "It isn't clear if this is because dense breasts predispose a woman to breast cancer.

However, studies do show that mammography is not as sensitive in detecting cancers in dense breasts."

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In fact, a 2007 study suggested that 35 percent of breast cancer goes undetected by mammography in women with dense breasts, and that, as breast density goes up, the accuracy of mammograms goes down. The reason for this disparity is that while fatty tissue appears dark on a mammogram, dense tissue appears white--but so do potentially cancerous areas, meaning they can blend in.


"Radiologists typically describe trying to find cancers in very dense breasts as being as difficult as trying to see a polar bear in a snowstorm," says Dr. Babagbemi. This means that, in many cases, tumors in women with dense breasts may go undetected until their cancer is at a more advanced stage."


Ultrasound more effective --

As part of the ABUS approval process, the FDA reviewed results from a clinical study in which board-certified radiologists were asked to review mammograms alone or in conjunction with ABUS images for 200 women with dense breasts and negative mammograms. Use of the ABUS, which can scan the entire breast in about one minute, increased cancer detection by about 30 percent in these women; the rate of false positives rose by four percent). A 2010 study showed that ABUS also tripled detection rates for cancers smaller than 10 millimeters in size.


Dr. Babagbemi says that ultrasound, which uses high-frequency sound waves, can detect smaller tumors in dense breasts. "With that in mind, physicians can choose to offer additional screening using ultrasound for women with dense breast tissue who have had a negative mammogram," she says. "It is important to note, however, that some women with dense breasts may actually be better served by a screening MRI rather than ultrasound, particularly if they are at higher-than-average risk for breast cancer."


Dr. Babagbemi recommends that patients discuss screening ultrasound versus MRI with their radiologists or referring physicians based on their own unique risk factors. She also emphasizes that ultrasound does not replace mammography as a screening test; it is used in addition to mammography, even in women with dense breasts.


Some restrictions apply

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For women who have dense breasts, ABUS may be a significant advancement in their breast healthcare. But Dr. Babagbemi cautions that there are some restrictions.

"Women who have had a previous breast intervention, such as surgery or biopsy, won't be eligible for screening with the device, since an intervention might alter the appearance of breast tissue in an ultrasound image and make interpretation difficult," she explains. "These patients can be scanned with the standard hand-held ultrasound. Patients with fatty breasts also are not candidates for ABUS."


Another caveat to keep in mind is that radiologists often disagree on exactly what constitutes dense breasts. "We do have guidelines that help us decide," Dr. Babagbemi says, "and computer software also can be used to quantify breast density."

DEGREES OF BREAST DENSITYBreast density is classified using the BI-RADS (Breast ImagingReporting and Data System) scoring method developed by theAmerican College of Radiology. This method describes fourdifferent categories. Screening with ABUS is reportedly usefulfor improving cancer detection in types 3 and 4.Type 1 Breast tissue is almost entirely fatty. Mammogram is very effective at detecting cancer, sensitive even to small tumors; breast contains less than 25 percent glandular tissue.Type 2 Scattered fibroglandular tissue; minor decrease in mammogram sensitivity.Type 3 Heterogeneously dense tissue present; moderate decrease in mammogram sensitivity.Type 4 Extremely dense tissue present; marked decrease in mammogram sensitivity.Sowre: American College of Radiology/Breast Imaging and ReportingSystem
As yet, only a small number of states (see box) routinely inform women if their mammogram indicates they have dense breasts. "If you don't reside in one of those states, the mammography results you receive will only summarize the findings of the mammogram and not breast density," says Dr. Babagbemi. But if you would like this information, you can ask your doctor for the 1 report generated by the radiologist, which will include an assessment of your breast tissue."


ABUS is already approved as a screening adjunct for women with dense breasts in Canada and 27 European Union countries. However, Dr. Babagbemi notes that it may take some time for ABUS to be available in all practice settings, as it is still a new technology.

"Widespread implementation of new technology often takes time and requires practitioners to acquire necessary skill sets and training to use it properly," she explains. "Weill Cornell currently does not have this technology."


WHAT YOU SHOULD KNOW

About breast density:

* According to a 2010 Harris Interactive Poll, 95 percent of women don't know their breast density, and that doctors have spoken to less than one in 10 women age 40 and older about breast density.

* In most states, doctors aren't required to directly inform women if they have dense breasts.

* Connecticut, Texas, Virginia and New York have passed laws requiring that mammogram providers notify women if they have dense breasts when they mail out test results. Similar legislation has been introduced in other states and in Congress: Keep track of progress at www.areyoudense.org.

Additionally, North Carolina and California just passed legislation making it the law for doctors to inform women who have dense breasts.



Source Citation (MLA 7th Edition)
"New ultrasound system approved for screening dense breasts: cancer can be difficult to detect in dense breasts screened with mammography, but ultrasound makes cancer easier to see." Women's Health Advisor 16.11 (2012): 1+. Health Reference Center Academic. Web. 28 Oct. 2013.


Andi