Special Report

When an expert panel updated its breast cancer screening recommendations last fall, it unleashed a tidal wave of confusion among women in their 40s about whether they need annual mammograms.

Among the recommendations, the U.S. Preventive Services Task Force advised against routine yearly mammograms for most women under 50. Instead the panel recommended that such women, lacking specific risk factors—such as a history of chest radiation or a genetic mutation indicating risk of breast cancer—talk to their doctor about mammography’s pros and cons for their age group before beginning screening. “The decision … should be an individual one,” the task force wrote. The task force based its current recommendations on an independent scientific review of data, including recent research designed to examine mammography’s impact on women in their 40s.

Expert guidance on this topic has varied for more than a decade. For instance, the same task force, in its 2002 guidelines, noted that “the precise age at which the benefits from screening mammography justify the potential harms is a subjective judgment.” Advocacy organizations, meanwhile, have also differed regarding women under 50. Groups including the American Cancer Society and Susan G. Komen for the Cure call for routine yearly mammograms for virtually all women 40 and older, while others, including the American College of Physicians and National Women’s Health Network, don’t.

Although mammography’s benefits are clear for women ages 50 to 74, the picture is murkier for women 40 to 49. That’s because these women are less likely to get breast cancer (although when they do, it often is more aggressive). And mammography in younger women is more likely to yield “false-positive” results—meaning women are subject to anxiety, inconvenience, and unnecessary medical procedures while a suspicious but benign spot is investigated.

“For women ages 40 to 49, the cumulative risk of having a false-positive examination after 10 years is about 50 percent, compared to a breast cancer risk of less than 2 percent and a probability of having one’s life saved of 0.05 percent,” says Ellen Warner, MD, of Sunnybrook Health Sciences Centre in Toronto. “So all women will have the annoyance and anxiety of a mammogram; [over time] almost half will have the horrible anxiety of a false-positive; all of society will bear the expense; but very few women will benefit.

“On the other hand, for those few whose lives are saved and their families … then the gains are enormous.”

Such polar views of benefit versus harm lie at the crux of the controversy. “The actual evidence hasn’t really changed much, but one can interpret it in very different ways,” Warner says. For instance, given that breast cancer is the leading killer of women ages 40 to 49, “how can we not screen women and save lives?” she says.

But screening’s benefits are diminished because breast cancer is less common, and mammography is less effective—including sometimes providing “false-negative” results, where cancer is present but goes undetected—in younger women.

“This is all to say that as a public policy, yearly mammograms in all women aged 40 to 50 are probably not a good idea,” contends Susan Love, MD, president of the Dr. Susan Love Research Foundation, “while it still might be important for certain high-risk women.” Unfortunately, most young women who develop breast cancer have no obvious risk factors, Warner says.

The decision to begin or delay mammography ultimately lies in the hands of patients and doctors. Warner, who herself didn’t begin screening until age 50, believes any younger woman who is anxious about cancer—such as those with lumpy breasts who fear cancer will be hard to detect—should get a mammogram if she wants. “It will be their choice,” she says.

At the 2009 San Antonio Breast Cancer Symposium, Ellen Warner, MD, discussed the controversy regarding the latest recommendations for mammography screening. Listen to her interview at www.curetoday.com/video/ellenwarner.