Confused about mammography guidelines? 7 questions answered
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.
IN THIS ARTICLE
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?
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.
Among professional organizations, a resounding chorus of disagreement
After publication of the new US Preventive Services Task Force (USPSTF) breast cancer screening guidelines late last year, it was only a matter of hours before official bodies and professional organizations began to weigh in on the changes, and the verdict was unanimous—disagreement. Among those chiming in were the American Cancer Society (ACS), the American College of Obstetricians and Gynecologists (ACOG), the American College of Radiology, the American Society of Breast Surgeons, the Society for Breast Imaging (SBI), and Susan G. Komen for the Cure, among others. Here are excerpts from their statements.
American Cancer Society
The ACS immediately refuted the USPSTF recommendations:
The American Cancer Society continues to recommend annual screening using mammography and clinical breast examination for all women beginning at age 40. Our experts make this recommendation having reviewed virtually all the same data reviewed by the USPSTF, but also additional data that the USPSTF did not consider….[T]he American Cancer Society’s medical staff and volunteer experts overwhelmingly believe the benefits of screening women aged 40 to 49 outweigh its limitations. 7
The College reaffirmed its support for screening mammography every 1 to 2 years in women 40 to 49 years old and every year for women 50 and older, as well as breast self-examination for women of all ages:
At this time, The American College of Obstetricians and Gynecologists recommends that Fellows continue to follow current College guidelines for breast cancer screening. Evaluation of the new USPSTF recommendations is under way. Should the College update its guidelines in the future, Fellows would be alerted and such revised guidelines would be published in Obstetrics & Gynecology. 5
American College of Radiology
The College minced no words in opposing the changes:
If cost-cutting US Preventive Services Task Force (USPSTF) mammography recommendations are adopted as policy, two decades of decline in breast cancer mortality could be reversed and countless American women may die needlessly from breast cancer each year.
These new recommendations seem to reflect a conscious decision to ration care. If Medicare and private insurers adopt these incredibly flawed USPSTF recommendations as a rationale for refusing women coverage of these life-saving exams, it could have deadly effects for American women,” said Carol H. Lee, MD, chair of the American College of Radiology Breast Imaging Commission. 8
American Society of Breast Surgeons
The organization released a statement describing its position as “strongly opposed” to the USPSTF recommendations:
We believe there is sufficient data to support annual mammography screening for women age 40 and older. We also believe the breast cancer survival rate of women between 40 and 50 will improve from the increased use of digital mammographic screening, which is superior to older plain film techniques in detecting breast cancer in that age group.
While we recognize that there will be a number of benign biopsies, we also recognize that mammography is the optimal screening tool for the early diagnosis of breast cancer in terms of cost-effectiveness, practical use, and accuracy. 9
Society for Breast Imaging
In its statement, the SBI noted the confusion caused by revision of the USPSTF guidelines, calling it “unnecessary and potentially deadly”:
Mammography has been shown unequivocally to save lives and is primarily responsible for the 30% decline in breast cancer mortality in the United States over the past 20 years. The USPSTF conclusion—that women under age 50 should not undergo routine screening—conflicts with their own report, which confirms a benefit of mammography to women age 40–49 that is statistically significant.
We strongly urge women and their physicians to adhere to the American Cancer Society recommendations of yearly screening beginning at age 40. 10
Susan G. Komen for the Cure
This public advocacy group issued a statement in late November acknowledging “mass confusion and justifiable outrage” in the aftermath of the USPSTF changes:
”We have worked so hard to build public trust and urge people to get screened,” said Nancy G. Brinker, founder of Susan G. Komen for the Cure, “and now they hear that maybe they shouldn’t bother. That is dangerous….Let me say this as clearly as I can: Mammography saves lives, even this report says that. Keep doing what you are doing. And always, talk with your doctor.” Brinker also noted that Komen for the Cure was not changing its guidelines, continuing to recommend annual mammograms beginning at age 40. 11
3. Why have the guidelines captured so much media attention?
Most of the controversy that has arisen since publication of the new guidelines has centered on the recommendation against screening mammography in women 40 to 49 years old. A number of media outlets have highlighted women whose breast cancer was detected by screening mammography when they were in their 40s, and many survivors with a similar history have spoken out against the new recommendations.
In addition, the American Cancer Society (ACS), the American College of Radiology, Susan G. Komen for the Cure, and other groups have publicly opposed the new guidelines. (See “Among professional organizations, a resounding chorus of disagreement”)
4. What is ACOG’s position on the new recommendations?
The American College of Obstetricians and Gynecologists (ACOG) was quick to weigh in on the new USPSTF guidelines, emphasizing that the College’s recommendations have not changed. They include:
- screening mammography every 1 to 2 years for women 40 to 49 years old
- screening mammography every year for women 50 years and older
- BSE for all women.
ACOG did note, however, that “the College is continuing to evaluate in detail the new USPSTF recommendations and the new evidence considered by the USPSTF.” 5
5. What do thought leaders make of the USPSTF changes?
Although the USPSTF guidelines sparked a firestorm of media coverage, the change did not come as a shock to leaders in the ObGyn specialty.
Legitimate concerns about screening mammography have increasingly been raised by experts in the field.
ANDREW M. KAUNITZ, MD “I was not surprised,” said Dr. Kaunitz. “As I pointed out in my editorial in OBG Management, legitimate concerns about screening mammography have increasingly been raised by experts in the field. 2 Proposals to stop routinely screening women in their 40s were made earlier in this decade, but were met with major pushback from the ACS, breast cancer advocacy organizations, and medical specialty groups. These same groups are now pushing back against the new USPSTF guidelines,” he added.
Robert L. Barbieri, MD, was not taken aback by the guidelines themselves, but he was surprised by the manner and timing of their release. Dr. Barbieri is Kate Macy Ladd professor of obstetrics, gynecology, and reproductive biology at Harvard Medical School and chief of obstetrics and gynecology at Brigham and Women’s Hospital in Boston. He serves as editor-in-chief of OBG Management.