Clinical Review

Confused about mammography guidelines? 7 questions answered

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Breast cancer screening recommendations issued by the US Preventive Services Task Force succeeded—in clouding what’s best, for whom. But the air is clearing and answers have emerged.



Some clinicians were reconsidering the need for an annual mammogram even before the US Preventive Services Task Force (USPSTF) issued new guidelines late last year.1

Andrew M. Kaunitz, MD, is one of those clinicians. In an editorial in the December issue of OBG Management, he was bold enough to declare: “My plan is to be more acquiescent when a woman says ‘No’ to an annual mammogram.”2

Among the evidence he cited to justify that acquiescence was a recent article in the Journal of the American Medical Association that expressed concern about the high number of early cancers—including ductal carcinoma in situ—that are detected by mammography and treated even though many are unlikely to progress or ever become clinically significant.3 This phenomenon—termed “over-diagnosis”—is one of the risks of breast cancer screening.

Dr. Kaunitz is professor and associate chairman of obstetrics and gynecology at the University of Florida College of Medicine–Jacksonville. He also serves on the OBG Management Board of Editors.

Although the USPSTF is the only official body to revise its recommendations on breast cancer screening so far, more changes seem likely. This article aims to sift through the static on the airwaves of late and offer concrete recommendations for practice. In the process, it addresses seven questions:

  • How did USPSTF guidelines change?
  • Why did they change?
  • Why did the changes attract so much attention?
  • What is ACOG’s position?
  • What do thought leaders make of the new guidelines?
  • Are the USPSTF recommendations likely to affect insurance coverage for mammography?
  • What should you tell your patients about breast cancer screening?

1. How did USPSTF guidelines change?

In an article published November 16, the USPSTF made a number of revisions to earlier breast cancer screening guidelines for women at average risk of the disease:

Approximately 39 million women undergo mammography each year in the United States, costing the health-care system more than $5 billion.

  • Routine screening mammography is no longer recommended in women 40 to 49 years old. Rather, the decision about when to begin regular screening should be individualized and should “take into account patient context, including the patient’s values regarding specific benefits and harms” (Grade C recommendation).
  • Screening mammography in women 50 to 74 years old should be biennial rather than annual (Grade B recommendation).
  • Breast self-examination (BSE) is not recommended for any age group (Grade D recommendation).1

2. Why did the USPSTF guidelines change?

The changes were based on new data and analysis in the following areas:

  • Mortality among women 40 to 49 years old. Although mammography screening reduces breast cancer mortality by 15% in this age group, the USPSTF concluded that “there is moderate certainty that the net benefit is small” in this population.1,4
  • The effectiveness of BSE in decreasing breast cancer mortality among women of any age. Studies of BSE published since 2002 found no significant differences in breast cancer mortality between women who perform BSE and those who don’t.4
  • The magnitude of harms of screening with mammography. Mammography screening in women 40 to 49 years old involves a significant risk of harms.4 Although the USPSTF observed that the benefits of mammography in women 40 to 49 years old appear to be equivalent to the benefits of mammography among women 50 to 59 years old, it concluded that the harms outweigh benefits in the younger women.

Harms cited by the USPSTF include:

  • radiation exposure
  • pain during the procedure
  • anxiety and distress
  • an increased rate of false-positive results
  • greater need for additional imaging and biopsies.4

The USPSTF conceded that the radiation exposure from a mammogram is minimal, but questioned whether cumulative exposure in young women might be problematic. It also noted that “many women experience pain during the procedure (range, 1% to 77%), but few would consider this a deterrent from future screening.”4

As for false-positive results, the group observed: “Data from the [Breast Cancer Screening Consortium (BCSC)] for regularly screened women…indicate that false-positive mammography results are common in all age groups but are most common among women aged 40 to 49 years (97.8 per 1,000 women per screening round).”4

“The BCSC results indicate that for every case of invasive breast cancer detected by mammography screening in women aged 40 to 49 years, 556 women have mammography, 47 have additional imaging, and five have biopsies.”4

It is the significant rate of false positives that creates the need for additional screening, diagnostic imaging, and biopsy. These additional imaging and invasive procedures increase anxiety and distress among many women. The USPSTF concluded that these harms outweighed the benefits of mammography screening in women 40 to 49 years old.


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