Why mammograms are needed

Dr. Alfred O. Berg, chairman of the U.S. Preventive Services Task Force on mammography, is chairman of the department of family medicine at the University of Washington.

Question: Are you surprised at the furor over mammography screening guidelines?

Answer: I must say the controversy has surprised me a bit. There's not much new out there. Basically, we (proponents and opponents of routine mammography screening) are all looking at the same information. Some individuals are making different assessments from the information. A lot of the controversy heated up in recent months, and it just happened to be during the interval in which we were completing our recommendations.

Q: Were federal health authorities concerned that women were starting to skip mammograms?

A: I can't answer that. What we do on the task force is we take interesting clinical questions and do scientific reviews. We avoid the public policy implications. We think it's important to answer the question "Does this work?" and leave it to others to figure out the policy implications.

Q: How do you account for the varying opinions on the value of routine mammography? Aren't people essentially disagreeing on the quality of the studies?

A: None of (the previous studies) were excellent-quality studies. Many were fair-quality studies. We did not think the flaws were significant enough to bias the results.

Q: Your recommendations state that there is no evidence that getting a mammogram every year is more beneficial than getting one every two years. Why not just recommend mammography every two years?

A: We try to call the science as it is and leave it up to the individual clinician and patient to decide what to do with it. We didn't find compelling evidence that one year was better than two years. Some people feel that there are reasons why a yearly interval makes sense -- such as to encourage the habits you'd like to see.

Q: Your recommendations for women ages 40 to 49 state that each individual woman and her doctor should decide when to start mammography and how often to have it. Were you trying to give women more freedom to choose?

A: We actually think the rigid benchmark of age 50 (for starting mammography regularly every one to two years) is somewhat arbitrary. The evidence of benefit is clearly strongest for women over age 50. There is evidence that it is effective for women under age 50, but younger women are also more likely to have false positives and unnecessary biopsies.

Q: The task force decided not to recommend for or against breast self-exam or clinical breast exam, and stated that self-exam may even be harmful by leading to false positives and unnecessary biopsies. Why not recommend not doing it?

A: There are some interesting studies that suggest more harm than benefit from doing breast self-exam. What we found was that there are only two well-controlled, randomized trials on the benefits of breast self-exam. Those trials suggest that breast self-exam doesn't work. It produces false positives and lots of anxiety. But we weren't comfortable saying we shouldn't (do breast self-exam) in the United States. Both the studies came from other countries, and we came to the conclusion that they may not apply to our population. I can tell you our recommendation is neither a recommendation not to do it or to do it. It's neutral.