Q& A

A difference of opinions on mammograms

  Enlarge Photo    
Tuesday, November 24, 2009

Last week, the U.S. Preventive Services Task Force published new guidelines that recommended against routine mammography screening for women in their 40s and less-frequent screening for older women at average risk of developing breast cancer. The guidelines also said there was no evidence to support doctors' teaching women to do breast self-exams. The changes prompted confusion among many patients as well as accusations that the changes amounted to rationing health care. The Post posed some questions to Kay Dickersin, director of the U.S. Cochrane Center and the Center for Clinical Trials at the Johns Hopkins Bloomberg School of Public Health. In 1997, as a member of the National Cancer Advisory Board, Dickersin voted in support of similar recommendations for women ages 40 to 49. She also received a diagnosis of breast cancer in 1986.

Are the new recommendations well thought-out?

Yes. The recommendations were made by a group of doctors based on their interpretation of two studies done by researchers who are trained and skilled in relevant research methods. One study was a synthesis of research data on the effectiveness of screening in terms of health outcomes, and the other study involved creating a set of six different statistical models to examine how often women should be screened, given different assumptions.

Then why are they so controversial?

I can imagine that the public might wonder why a procedure that prevents a disease would be taken away.

But mammography doesn't prevent breast cancer, it merely detects it. And detecting it earlier doesn't necessarily mean a life is saved or even extended.

The idea of early detection is that we are catching cancer before it does damage. But we know now that this is not always the case, and sometimes we merely detect something that wouldn't have harmed a woman anyway. In other cases we are detecting a cancer earlier but can't change the course of the cancer. In this case, women and their families live longer knowing they have cancer, but they don't actually live longer than they would have if the cancer had been detected earlier.

Often I hear a woman say something like, "My life was saved by because of a mammogram I got when I was 39 and breast cancer was detected." But we don't know that her life was saved by that mammogram. She might have found the lump herself the next day, in the shower, or the cancer might have been an "in situ" cancer that would not have become invasive and might never have harmed her. It seems to her as if the mammogram "saved her life," but we cannot know that, and if one looks across many women in her age group, we don't see that on average this would be true.

In 1986, I found a breast lump that turned out to be breast cancer. I was 34. Because of my age, I had never had a mammogram. I sometimes wonder whether it would make just as compelling a sound bite if I said, "I found my own breast cancer without breast self-exam or mammography, and that's why I am still alive." While it is true that across populations taking early action against a breast cancer diagnosis saves lives, it is not always true that the method of detection can be credited. That is what the review is saying: Except in a few cases, we cannot credit mammography with saving women's lives in the 40-49 age group.

In deciding whether to get a mammogram, how should a woman consider factors such as family history?

Family history, especially a mother or sister getting breast cancer before menopause, is an important consideration. Women with a family history may be advised to have mammograms before age 50, depending on which relative had breast cancer and the age at which the relative was diagnosed.

What's the problem with doing breast self-exams?

CONTINUED     1        >

© 2009 The Washington Post Company