Digital Mammography and Breast MRI: What's Newer and Better Out There?

PJ Hamel Health Guide
  • Breast Cancer Screening News Update: Yesterday, March 27, the American Cancer Society issued new breast cancer screening guidelines calling for women in certain risk groups to be screened via MRI (magnetic resonance imaging), in addition to mammography. At the same time, the March 29 issue of the New England Journal of Medicine, includes a national study indicating that women who’ve been diagnosed with cancer in one breast should have an MRI in the other, as MRI can detect very early cancers that can’t be seen on a mammogram. Together they signal a sea change in how certain women should be screened for breast cancer. -- PJ Hamel
    Add This Infographic to Your Website or Blog With This Code:

    Originally published January 5, 2007

    For years, mammograms have been the universally recommended way for women to double-check the health of their breasts. We’re surrounded by reminders to get a yearly mammogram: from the American Cancer Society, with their tasteful ads; from doctors, who routinely call for it as part of a woman’s post-40 physical; and from our sisterhood of family, friends, and colleagues, who nag relentlessly if we put it off.

    While “the big squeeze” isn’t pleasant, it’s at least familiar, to those of us who’ve been having an annual film mammogram for years. And for those of you who haven’t yet reached mammogram age: don’t sweat it. It’s not as uncomfortable as you probably imagine, it only lasts a few seconds and, as you move into prime breast cancer territory–women over 40–it provides you with a big “whew, I‘m set for another year!” moment.

    Standard film mammograms start with a baseline reading: the first mammogram you have is your baseline. Each year after that, the mammogram is compared to the one from the previous year, to note any changes. Mammograms are about 80 to 85 percent effective in detecting tumors, including very small ones, ones that can’t be felt during a self-exam, or even by a doctor during your physical. They’re the Ford Escort of breast cancer detection: familiar, reliable, and reasonably priced. But, just as the Escort is gradually disappearing from the roads (it ceased production 5 years ago), are standard film mammograms becoming a thing of the past, replaced by newer, possibly more accurate technologies?

    The digital mammogram is already available at about 10% of breast imaging facilities. It relies on a breast X-ray, just as a film mammogram does, but instead of being recorded on film, it’s electronic: it can be magnified, made darker or lighter, and otherwise tweaked, so the radiologist reading it can get the very best view. It’s also much easier to store, retrieve, and send from place to place; unfortunately, it’s also up to four times as expensive as a film mammogram. Studies have shown that a digital mammogram is more accurate in detecting cancer in three groups of women: those under 40; those who are pre- or peri-menopausal; and those with particularly dense breasts. If you fall into any of these groups, ask your doctor if digital mammography is available–and then ask your insurance company if they cover it.

  • The MRI (magnetic resonance imaging) is technology that’s been in use for years, but only recently has become a player in breast-cancer screening. It uses a magnet and radio waves to create 3-D cross-section images of your breasts; an injection of a contrast agent prior to the exam helps highlight any areas of abnormality. Well, that sounds pretty cutting-edge, you think. But hold on. Breast MRIs, thus far, have proven better than mammograms in only one way: clarifying abnormalities picked up on a regular film or digital mammogram. They’re not yet approved by the FDA as a general-population breast cancer screening tool (though they are recommended for young women whose genetics place them at high risk for cancer, as MRIs are particularly accurate detecting tumors in dense breasts, and younger women generally have denser breasts).
    Add This Infographic to Your Website or Blog With This Code:

    MRIs are a bigger deal than mammograms, too, in all ways; they’re up to 10 times as expensive, they take up to 10 times as long (including the injection), and they can be quite uncomfortable, if you’re prone to claustrophobia. Bottom line: useful if a problem is discovered or suspected, but as an adjunct to, not a replacement for, the standard mammogram.

    Finally, you may have heard of CAD: computer-aided detection. CAD is simply software that scans a digital mammogram, highlighting potential problem areas that your radiologist might not have been able to see. Its main benefit is its accuracy: it’s been found to detect approximately 20% more cancers than were detected by a radiologist’s reading alone. It’s also reasonably priced; it adds just $10 to $15 to the cost of your mammogram. However, it works only with digital (not film) mammograms; some hospitals choose to scan and digitize film in order to use CAD along with their film mammography units. Plus, the cost of implementing the CAD system is high, so most hospitals have yet to adopt it. Again, bottom line: useful as an add-on, but not a replacement for mammography.

    So, where do we stand, among all this technology? “The big squeeze”–the standard mammogram, whether digital or film–is still the diagnostic tool of choice for breast cancer detection. CAD software can double-check the radiologist’s reading, and an MRI can clarify suspected problems, but for now, the mammogram is still your weapon of choice for early breast cancer detection.

Published On: March 28, 2007