Digital Tomosynthesis Improves Early Detection of Breast Cancer
In 2011, Memorial Hermann was the first hospital system in the southern part of Texas to introduce a new, leading-edge digital technology that improves radiologists’ ability to detect smaller tumors at the earliest stages of breast cancer, especially in women with dense breasts. Today, digital breast tomosynthesis is available at 15 Memorial Hermann locations around the city.
“Digital tomosynthesis creates a highly focused 3-D image of the breast that aids in detection of small tumors earlier than traditional mammograms, which is especially important for women with dense breast tissue,” says Anne C. Kushwaha, M.D., a diagnostic radiologist at Memorial Hermann Breast Care Center-Upper Kirby, Memorial Hermann Breast Care Center-Southwest and Memorial Hermann Bobetta Lindig Breast Care Center-Memorial City. “Radiologists examine mammograms to rank tissue density in four categories: almost entirely fatty (category 1), scattered areas of fibro-glandular tissue (category 2), heterogeneously dense (category 3), and extremely dense (category 4). Women with any breast density beyond fatty tissue, which includes those in categories 2 through 4, should get digital tomosynthesis. This is 90 percent of women.”
Fat appears dark on mammograms, while fibro-glandular tissue and cancers appear white. Because it’s difficult to see white on white, malignant masses may be obscured by fibro-glandular tissue when viewed with traditional 2-D mammography. This is called masking; some cancers may be hidden by the overlying tissue and not detectable to the radiologist. Tomosynthesis can be performed at the same time as traditional mammograms to boost accuracy. Much like computed tomography, tomosynthesis takes a series of low-dose exposures that are mathematically processed into 1-millimeter slices that visualize breast tissue in three dimensions, removing spatial ambiguity.
“Digital breast tomosynthesis takes a sweep through the breast, allowing us to see several slices and reducing the possibility of a malignancy being hidden by overlapping tissue caused by compression,” says Dr. Kushwaha, an associate professor in the department of Diagnostic Radiology at The University of Texas MD Anderson Cancer Center. “Dense breast tissue can look similar to cancer on a mammogram. Tomosynthesis makes it easier to distinguish between dense tissue and malignancies, and allows radiologists to look at isolated areas of the breast in greater detail. We find cancers that might not be found on traditional 2-D imaging. In addition, tomosynthesis has been shown to reduce the number of false positives resulting in fewer women being called back for more tests.”
There’s another issue for women with dense breasts: They have double the cancer risk compared to the average, similar to the risk associated with a family history of breast cancer. The topic is currently under investigation.
Although cancer may be more difficult to spot on traditional mammograms, they are the only exam proven to lower mortality in women. “Mammograms detect early signs of cancer, including calcifications that can’t be felt during a manual breast exam,” Dr. Kushwaha says. “Women with heterogeneously dense or extremely dense breasts can request an ultrasound for additional screening, as it has been shown to increase the number of cancers detected. For women with a lifetime risk of breast cancer greater than 20 percent, an annual MRI is recommended in addition to mammography.”
Regardless of a woman’s breast density, yearly mammograms should start at age 40, or earlier in the case of a very high risk of breast cancer or the presence of a known mutation in either the BRCA1 or BRCA2 gene. There is no consensus on when women should cease annual mammograms. Most physicians recommend continuing screening mammograms as long as the woman is healthy. The American College of Radiology endorses breast tomosynthesis, saying recently, “Better sensitivity will likely translate into more lives saved.”
The technology is available at Memorial Hermann Breast Care Centers at Memorial Hermann Memorial City Medical Center, Memorial Hermann Katy Hospital, Memorial Hermann Southeast Hospital, Memorial Hermann Greater Heights Hospital, Memorial Hermann Sugar Land Hospital, Memorial Hermann Southwest Hospital, Memorial Hermann The Woodlands Hospital, Memorial Hermann Northeast Hospital, Sienna Convenient Care Center, Cypress Breast Care Center, CyFair Imaging Center, South Katy Imaging Center, Pearland Imaging Center, Victory Women's Imaging Center and Upper Kirby Breast Center.
For more information about breast cancer screening,click here.