The mammogram remains the foundation of breast cancer screening, but variations on this test can improve detection for some women.
The mammogram isn’t a perfect test, but it’s the best one we have right now for identifying breast cancers early, which is why it remains the cornerstone of breast cancer detection. “For the woman at average risk for breast cancer, it is the only proven screening test,” says Dr. Robyn Birdwell, associate professor of radiology at Harvard Medical School and section head in the Division of Breast Imaging at Brigham and Women’s Hospital.
A traditional mammogram produces an x-ray image of the breast on film, which the radiologist reads to look for changes that might be cancerous. But newer variations on the test may improve on its ability to detect cancer.
Digital mammograms also create x-ray images, but they’re stored on a computer instead of on film. The radiologist can then manipulate the images—enhancing or magnifying areas to see them more clearly. Although digital mammograms pick up about the same number of cancers as traditional x-rays, they may improve detection rates in women with dense breasts, which make tumors harder to spot. Digital mammograms have also helped bring down the number of recalls (women who need follow-up tests), says Dr. Birdwell. And they may expose women to less radiation per image than regular mammograms do.
3D mammograms are images produced from several x-rays of the breasts taken from different angles. Research suggests the 3D mammogram reduces recalls and slightly increases breast cancer detection rates. “It still has the limitations inherent in a mammogram,” Dr. Birdwell says. “But it finds things that are harder to see on a standard two-dimensional mammogram.” Not every medical center offers 3D mammography. Also, a 3D mammogram exposes women to slightly more radiation than a traditional one.
If you’re interested in a digital or 3D mammogram, ask whether you can have it done at the breast imaging center near you. These technologies may not be available at every facility. Also, Medicare will pay for a digital mammogram, but it generally does not cover the cost of 3D mammograms, which can run you an extra $50 or more.
Other screening options
For women at high risk for breast cancer, another important screening tool to consider is contrast-enhanced magnetic resonance imaging (MRI). In this test, a contrast material that shows up on an MRI scan is injected into the blood and circulates throughout the breast, where it highlights suspicious areas. “We know that in the high-risk population, MRI is more sensitive than mammography,” Dr. Birdwell says.
The American Cancer Society recommends contrast-enhanced MRI for women with a 20% to 25% lifetime risk of breast cancer. This includes women with a strong family history of breast or ovarian cancer and those who’ve been treated for Hodgkin’s disease. To learn your breast cancer risk, you can use an assessment tool available at the National Cancer Institute’s website,
Contrast-enhanced MRI is very sensitive at picking up breast cancers, but its increased sensitivity can also lead to a high rate of false-positive results. That is, the image shows something that could be cancer but turns out not to be. False-positive results lead to unnecessary biopsies and a lot of worry. If you have a very high likelihood of developing breast cancer—for example, because of a BRCA gene mutation—that’s a risk that may well be worth assuming. (BRCA1 and BRCA2 genes produce proteins that repair damaged DNA. Mutations in these genes can prevent DNA repair, significantly increasing your breast cancer risk.)
Important decisions and future directions
Your individual risk for breast cancer and your personal preferences are very important elements in deciding the right screening approach for you. Which test you have—if any—and how often you have it depend on your risks, including your personal and family history of the disease. It’s a matter you need to discuss with your primary care physician or gynecologist.
A few potentially more sensitive screening technologies are currently in development. One is breast-specific gamma imaging (also called molecular breast imaging), which uses a radioactive tracer to seek out cancerous tissue. Yet it may still be many years before we see a total transformation in breast cancer screening. “Nothing that I’m aware of is even near to replacing the mammogram,” Dr. Birdwell says. It is widely available, and it has been proven to have value in studies, she adds.