Getting the Content and the Message Right in Breast Cancer Screening Guidelines
As specialists in breast cancer screening, our concern is that the increasing number of differing recommendations creates confusion and a lack of clear direction for women—and their doctors—to effectively safeguard their breast health.
—Therese Bevers, MD, and Mark Helvie, MD
According to recent national headlines, the American Cancer Society (ACS) now recommends that women at average risk of breast cancer should “screen later and less often.”1 While the new ACS recommendations (summarized in this issue of The ASCO Post) might initially be taken as casting doubt on the value of “annual mammographic screening for women beginning at age 40,” when considering the nuances of the new ACS breast cancer screening guideline for women at average risk of the disease, the conflict is less pronounced than it appears in recent press coverage. As specialists in breast cancer screening, our concern is that the increasing number of differing recommendations creates confusion and a lack of clear direction for women—and their doctors—to effectively safeguard their breast health.
The ACS issued a “strong recommendation” that women with an average risk of breast cancer should undergo regular screening mammography starting at age 45 years. From the patient perspective, a “strong recommendation” means: “Most individuals in this situation would want the recommended course of action, and only a small proportion would not.”2
However, a number of qualified recommendations must be understood to fully appreciate the new guideline. In contrast to a strong recommendation, a “qualified recommendation” means: “The majority of individuals in this situation would want the suggested course of action, but many would not.” This “qualified recommendation” allows a great deal of latitude in the interpretation of the ACS recommendations.
The ACS “qualified recommendations” include:
- Women aged 45 to 54 years should be screened annually.
- Women should have the opportunity to begin annual screening between the ages of 40 and 44 years.
- Women 55 years and over should transition to biennial screening or have the opportunity to continue screening annually.
- Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer.
- The ACS does not recommend clinical breast examination for breast cancer screening among average-risk women at any age.
Interpreting the Guidelines
With these new recommendations, the ACS affirms that screening mammography saves lives. Specifically, fewer women will die of breast cancer as a result of early detection from routine screening mammography. Notably, and in contrast to recurring arguments against screening mammography, they did not find evidence that the value of mammographic screening has declined due to advances in breast cancer treatment.
Additionally, the new recommendations confirm the value of annual mammographic screening for women in their 40s. This is in direct contrast to the 2009 and 2015 draft U.S. Preventive Services Task Force (USPSTF) grade B recommendations for routine mammographic screening to be done biennially beginning at age 50.3,4Although the ACS recommends annual screening for women aged 45 to 54, the new guideline also allows the opportunity for women to begin annual screening mammograms at age 40 (qualified recommendation). In addition, while the ACS notes that women may transition to biennial mammographic screening at age 55, they also note that women should have the opportunity to continue annual mammographic screening (qualified recommendation).
These last two qualified recommendations have been consistently missing in the media coverage. On first review, the new ACS recommendations appear to endorse fewer mammograms and less frequent screening, resulting in the previously mentioned headlines. However, when distilled to its simplest form, a recommendation of “annual mammographic screening for average-risk women beginning at age 40 years” is not in conflict with the ACS recommendations. This perspective on the ACS recommendations also aligns with the National Comprehensive Cancer Network’s (NCCN) recommendations for annual mammographic screening beginning at age 40 after women are counseled regarding potential benefits, risks, and limitations of breast screening.5
Benefits vs Harms
The rationale for the qualified recommendations for annual screening of women aged 40 to 44 and women aged 55 and older (noted as “opportunities” for both age groups in the new guideline) relates to the perceived balance of benefits and harms. The ACS felt that this balance was less favorable for these women than for women aged 45 to 54. It is acknowledged that women at all of these ages are less likely to die of breast cancer if they undergo annual mammographic screening. However, the ACS identified concerns about the harms incurred as a result of screening mammography (largely false-positives), especially for women in their early 40s.
When considering the “harms” of false-positives of screening mammography, there are several perspectives to consider. First, there is no consensus on what constitutes “harm” and what value judgment women assign to the “harm” compared to the mortality reduction benefit. Many women who are called back for additional testing and for which the evaluation was benign feel reassured that every measure is being taken to ensure that there is no serious concern on their screening mammogram. These women do not label their call-back (a false-positive) as a “harm.”
In the ACS and USPSTF analyses, the harms of screening have been reported to be compared to the harms of “no screening.” However, the actual analysis has compared screening harms to the absence of harm among nonscreened women. Nevertheless, nonscreened women frequently develop breast symptoms that require diagnostic evaluation and biopsy, many of which will be benign (false-positive). A more appropriate analysis would be the “net” harms of screening vs no screening. The discussion of the benefits of mammographic screening (mortality reduction, less morbidity) should be balanced not only by the harms of screening (mostly false-positives) but also by the harms of not screening (cancers diagnosed at more advanced stages, increased mortality, and increased morbidity).
Clinical Breast Exam
An unanticipated recommendation from the ACS is the “qualified recommendation” against clinical breast exam for average-risk women of any age, citing a lack of evidence of any benefit alone or in conjunction with screening mammography. However, two international studies have suggested that a clinical breast exam may have value in breast cancer screening.6,7
It is surprising that ACS made a strong negative recommendation absent new scientific evidence that benefits were lacking or the harms were significant. Of note, while the value of clinical breast exam remains to be determined, the clinical encounter provides an opportunity to evaluate a woman’s risk of breast cancer and have a discussion regarding risk reduction strategies, such as preventive therapies (eg, tamoxifen and raloxifene) and the importance of a healthy lifestyle.
After review of the new ACS Breast Cancer Screening recommendations, the NCCN Breast Cancer Screening and Diagnosis guideline panel, noting that no new data were available since the last annual review, did not recommend any changes to their recommendations for breast cancer screening. The NCCN continues to recommend annual clinical breast examination and screening mammograms for women beginning at age 40 and continuing for as long as they have a 10-year life expectancy. Our mission is to save lives, and the data indicate that this is the best way to do just that.
Addressing the Confusion
Women at average risk are now confronted with different guidelines, each suggesting screening mammograms beginning at different ages and at differing intervals. Subtle differences in the ACS affirmative recommendations between “most” and “majority” are very nuanced. However, in the end, the ACS guidelines support annual screening mammograms beginning at age 40.
In an attempt to address the confusion of these differing guidelines, a Consensus Conference is being convened by the American College of Obstetricians and Gynecologists in January 2016. Major organizations, including ACS, NCCN, and other providers of women’s health care will gather to evaluate and interpret the data with the intent of developing a consistent set of uniform guidelines for breast cancer screening that can be implemented nationwide.
We are appreciative that a national organization of primary care providers has identified the critical need for a uniform recommendation for breast cancer screening and taken action. This upcoming conference provides a beacon of hope that a number of major organizations can agree on breast cancer screening recommendations and provide unified guidance to women and their clinicians. ■
Disclosure: Drs. Bevers reported no potential conflicts of interest. Dr. Helvie has received an institutional grant with GE Healthcare for tomosynthesis.
1. Cohen E: New breast cancer screening guidelines: Screen later, less often. CNN.com, October 22, 2015. Accessed October 28, 2015.
2. Oeffinger KC, Fontham ET, Etzioni R, et al: Breast cancer screening for women at average risk: 2015 guideline update from the American Cancer Society. JAMA 314:1599-1614, 2015.
3. U.S. Preventive Services Task Force: Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 151:716-726, 2009.
4. U.S. Preventive Services Task Force: Draft recommendation statement for breast cancer screening. Available at www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementDraft/breast-cancer-screening. Accessed November 10, 2015.
5. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®): Breast cancer screening and diagnosis (version 1.2015). Available at NCCN.org. Accessed November 10, 2015.
6. Mittra I, Mishra GA, Singh S, et al: A cluster randomized, controlled trial of breast and cervix cancer screening in Mumbai, India: Methodology and interim results after three rounds of screening. Int J Cancer 126:976-984, 2010.
7. Sankaranarayanan R, Ramadas K, Thara S, et al: Clinical breast examination: Preliminary results from a cluster randomized controlled trial in India. J Natl Cancer Inst 103:1476-1480, 2011.
Dr. Bevers is Professor, Clinical Cancer Prevention; Medical Director, Cancer Prevention Center, The University of Texas MD Anderson Cancer Center; Chair, Breast Cancer Screening and Diagnosis Guideline Panel, National Comprehensive Cancer Network. Dr. Helvie is Professor, Department
of Radiology, Comprehensive Cancer Center, University of Michigan Health System; Vice-Chair, Breast Cancer Screening and Diagnosis Guideline Panel, National Comprehensive Cancer Network.
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