Ask Dr. Marie: Mammograms Not Always a Good Idea

Feb. 11, 2009— -- Two recent studies remind me that frequent and early screening mammograms may not always (emphasis on "not always") be a good idea.

The first study in the Journal of the American Medical Association looked at women who received chest radiation as a child and found that only about half of the women had a screening mammogram within the previous two years, despite evidence that their exposure to radiation as children may increase their risk of breast cancer.

The article's headline seemed to suggest that women with such a risky history were in some way negligent when, in fact, they (or their doctors) may have been appropriately cautious about doing too many X-rays. An accompanying editorial wisely suggested that maybe women with childhood radiation should have less exposure to X-rays rather than more exposure. The editorial raised the question about whether perhaps breast MRIs would be a better way to screen high-risk women with a history of childhood radiation to avoid unnecessary and potentially risky X-ray exposure.

The second study questioned whether the current recommendations for women who have inherited one of the two known breast cancer genes, BRCA 1 or BRCA 2, to begin screening mammograms at age 25 or 30 makes good sense.

Researchers looked at a mathematical model calculating radiation exposure in young women receiving regular mammograms and compared this potential risk to increase breast cancer from X-rays to the potential benefit of starting mammograms at a young age. Their model suggested the increased risk of breast cancer from exposure to the radiation by doing the X-rays may outweigh any benefit of screening for young women at high risk for cancer because they have inherited one of the breast cancer genes, BRCA 1 or 2.

These studies take me back to the early 1980s when the controversy around the benefits versus the risks of mammograms took center stage in the screening debate.

The argument against mammograms back then was as follows: Because mammograms require exposure to ionizing radiation, a known risk factor for breast cancer, why would you expose a woman's breast to this radiation year after year with only marginal hope that a cancer will be detected early enough to improve outcome?