Early Mammogram Has Pros and Cons

Screening mammography every 1–2 years may be appropriate for women in their 40s, but only after an in-depth discussion of their individual cancer risks and the benefits and risks that mammography might confer, according to new guidelines published by the American College of Physicians.

The ACP recommendations differ from those of other major associations, including the American College of Obstetricians and Gynecologists, the American Cancer Society, and the U.S. Preventive Services Task Force, all of which recommend routine screening mammography every 1–2 years for women in their 40s.

The ACP document and accompanying patient guide urge women aged 40–49 to take an active part in the decision-making process by knowing their breast cancer risk profile and examining their concerns about mammography risks, including false-positive results, overdiagnosis of ductal carcinoma in situ, and the potentially unnecessary procedures that may follow (Ann. Int. Med. 2007;146:511–5).

“We believe that women in this age group need much more information about the risks and benefits of screening mammography before they make a decision,” Dr. Lynne M. Kirk, president of the ACP, said in an interview. “Rather than simply saying ‘Let's just do it,’ what we are saying is ‘Let's talk about it and then do it, if it makes sense for you.’”

The ACP guidelines should not be interpreted as a step back from routine screening, Dr. Kirk said. Instead, they are an effort to educate younger women about the balance between risk and benefit and to advance informed decision making. After discussion with their physicians, “many women will still choose to have the mammogram, but they will be doing it in a more informed fashion.”

The recommendations are based on a review of 117 studies, which concluded that for women in this age group, the benefits of screening mammography are fewer and the risks are greater than previously recognized (Ann. Int. Med. 2007;146:516–26), said Dr. Joann Elmore, professor of medicine at the University of Washington, Seattle. Dr. Elmore's editorial on the topic was published along with the guidelines (Ann. Int. Med. 2007;146:529–31).

Dr. Elmore explained in an interview that “if you have 10,000 women in their 40s receiving annual screens for 10 years—100,000 screens—you will only save a few lives, perhaps six. In other words, 9,994 women will derive no benefit at all from these screens.”

By the end of the 10-year period, about 50% of the women will have had at least one false-negative screen and an attendant diagnostic work-up. “About 2,000 will eventually undergo a breast biopsy,” which would turn out to be negative, she said.

Dr. Kirk and Dr. Elmore both acknowledged that it may not be easy for clinicians to find the time to conduct a detailed risk-benefit analysis for each eligible woman, and women will need to invest more effort into their health care decisions.

“Health information is already one of the top things for which the public uses the Internet,” Dr. Kirk said. “Several organizations, including the National Institutes of Health, offer online calculators for women to assess their own breast cancer risk. We would hope that women will use these tools in the context of discussion with their physician.”

But physicians should be aware that a joint decision to defer screening mammography could have legal ramifications, Dr. Elmore said. “The most common medicolegal allegation in the U.S. for years has been failure to detect cancer, and breast cancer is the most common of these. Both radiologists and physicians are increasingly concerned about this.”

Legal precedent has already been set, she added. In 1999, Dr. David Merenstein, then a third-year resident, and a 53-year-old patient engaged in an informed consent discussion of the risks and benefits of prostate-specific antigen screening. The patient did not request screening and never saw Dr. Merenstein again. A few years later, the patient's new physician ordered a PSA test without having the risk-benefit discussion. The patient was diagnosed with incurable prostate cancer and sued Dr. Merenstein; the patient's attorney argued that the risk-benefit discussion was superfluous and that the PSA should have been ordered as a standard of care.

Although Dr. Merenstein was exonerated, his residency program was found liable for $1 million (JAMA 2004;291:15–6).

“Even if you document that you discussed risks and benefits, the U.S. legal climate makes this kind of thing difficult,” Dr. Elmore said. She suspects that physicians may continue to practice defensively by routinely ordering screening mammography for younger women.

“The legal aspect is probably a valid point,” Dr. Kirk said. “But this guideline limits itself to the existing evidence. What we are saying is that the available scientific evidence, plus the woman's desires on the matter, will lead you to move in a specific direction” with regard to screening.

Dr. Kirk added: “Women and physicians are both struggling with this. We need more information. One of the goals of this document is to stimulate more research for this age group. Hopefully, in another 5 or 10 years, we will be looking at much more precise tools” for deciding which women will derive the greatest benefit from screening mammography.