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Breast-screening guidelines updated after review of the latest science

Screening’s potential benefits need to be balanced against the potential harms of screening: overdiagnosis and overtreatment.

The data revealed that for every 10,000 women screened repeatedly over 10 years, four lives may be saved in women aged 40 to 49; eight in women aged 50 to 59; 21 in women aged 60 to 69; and 13 in women aged 70 to 74.
REUTERS/Enrique Castro-Mendivil

On Monday, the U.S. Preventive Services Task Force (USPSTF) finalized its updated advice about breast cancer screening.

Its recommendations are basically the same as in 2009, when the panel of experts ignited a firestorm of controversy by saying that the evidence does not support routine mammograms for women between the ages of 40 to 49 who are at average risk of breast cancer. They also recommend, as they did in 2009, that average-risk women between the ages of 50 and 74 need to have a mammogram only every other year, and that routine screening can cease for women aged 75 and older.

As in 2009, the panel continues to stress that although their recommendations reflect the best evidence to date on the balance between mammography’s benefits and harms, individual women should talk with their doctors about the screening schedule that works best for them.

Last fall, the American Cancer Society (ACS) revised its own guidelines, bringing them more in line with those of the USPSTF. The ACS now recommends that women at average risk of breast cancer start having mammograms at age 45 and continue them annually until age 54, when they can consider shifting to every-other-year screening.

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How times have changed. In 2009, the ACS had joined the often-nasty backlash to the USPSTF’s recommendations. 

Weighing the evidence

For their updated recommendations, which were published in the Annals of Internal Medicine, the task force reviewed all the latest science on the topic, including data on newer testing methods, such as ultrasound, magnetic resonance imaging (MRI), and 3-D mammography.

The data revealed that for every 10,000 women screened repeatedly over 10 years, four lives may be saved in women aged 40 to 49; eight in women aged 50 to 59; 21 in women aged 60 to 69; and 13 in women aged 70 to 74. 

Those potential benefits need to be balanced, however, against the potential harms of screening: overdiagnosis and overtreatment. Mammograms often turn up false-positive results (lesions that are not cancer) or tiny cancers that may never progress or become life threatening.

The task force’s guidelines point out, for example, that for every 1,000 women aged 40 to 49 who undergo regular digital mammography screening, 121 have a false-positive result.

‘Time to douse the firestorm’

In an editorial published with the USPSTF’s updated recommendations, two editors at the Annals of Internal Medicine, Dr. Christine Laine and Dr. Cynthia Mulrow, along with Kay Dickersin, a professor of public health at Johns Hopkins University, write that it’s “time to douse the firestorm around breast cancer screening.” 

“As women who have had personal experiences with breast cancer and false-positive screening results and who devote much professional energy to evaluating medical evidence, we are concerned about efforts that conflate scientific evidence with policy decisions related to payment for health care,” they write. “These efforts also create unwarranted suspicion of the USPSTF’s work and divert attention and resources from gathering evidence to fill important gaps in knowledge about effective breast cancer prevention and screening.”

“Those gaps are wide and concern issues surrounding breast cancer screening about which we and many women worry,” they add. “For example, we need to identify better screening methods for all women, particularly those with dense breasts. We need to act on concerns about the prevalence of a more deadly form of breast cancer in African American women and promote research that evaluates the effect of screening in ethnic minority women. And we need to identify optimal strategies for the management of possible precursor lesions, such as ductal carcinoma in situ, while also better defining and quantifying the harms associated with overdiagnosis — an issue with direct application to screening mammography.”

Science vs. politics

As the editorial points out, the omnibus spending bill passed by Congress last December requires private insurers to fully cover mammography screening for women aged 40 to 49 years. Congress first mandated that requirement in 2009, in reaction to the political backlash to the USPSTF’s mammography recommendations.

“The public has had legitimate worry about whether copayment for mammograms would be required if a new recommendation were to supersede the special privilege accorded to the 2009 mammography recommendation,” Laine, Mulrow and Dickersin acknowledge. “But the target should not be the USPSTF, which cannot make payment decisions.”

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Any attacks on the task force’s evidence-based recommendations raises yet again “a question about acceptable boundaries when politics meets science,” they write.

Scientific evidence, not politics, they stress, must guide us in our decisions about health care:

Guidelines that mislead women about the net health benefits they can expect from mammography would disrespect our mothers, wives, daughters, and sisters. When the USPSTF posted its draft recommendations for comment, it noted, “Women deserve to be aware of what the science says so they can make the best choice for themselves, together with their doctor.”

We could not agree more. Let’s douse the flames and clear the smoke so that we can clearly see what the evidence shows and where we need to focus efforts to fill gaps in our knowledge so that women, along with their health care providers, can make the best decisions to reduce their risk for breast cancer-related morbidity and mortality. 

FMI: You can read the USPSTF’s guidelines at the task force’s website. The editorial is available at the Annals for Internal Medicine website.