American College of Physicians
Paul G. Shekelle
Douglas K. Owens
American College of Radiology
Steven E. Weinberger
Tuesday, Feb. 21, 2012
Breast cancer is the most frequently diagnosed non-cutaneous cancer and the second leading cause of cancer-related death among women in the United States. While screening mammography in women has been advocated by most professional organizations to detect breast cancer at a stage when it is still amenable to curative treatment, including the American College of Physicians (ACP), the American College of Radiology (ACR), as well as the U.S. Preventive Services Task Force, the age to initiate screening mammography in average risk women remains a point of contention (1-3). Both the ACP and the ACR have screening mammography guidelines for women between 40 and 49 years, but their recommendations differ for this age group. The ACR recommends that asymptomatic women 40 years of age or older should have an annual screening mammogram. The ACR rationale for this approach is that the overall benefits of mammography outweigh potential harms in women between 40 and 50 years of age, and almost all women would be willing to accept the risks of screening for the mortality benefit. The ACP guideline recommends a shared decision-making approach in women 40 to 49 years of age, and the decision to screen should be based on the benefits and harms of screening, the individual woman's preferences, and her breast cancer risk profile. The rationale behind ACP recommendation is that the benefits of mammography do not clearly outweigh the potential harms for women 40 to 49 years of age, and because of the potential risks, women should be fully informed rather than routinely screened.
In an attempt to better understand and reconcile their differences, the ACP and ACR held a face-to-face meeting with representatives from each organization to discuss the commonalities and differences between their guidelines, understand the reasons for these differences, and discuss the underlying evidence. We convened a one-day meeting with guideline development representatives from both the ACP and ACR on May 11, 2010, with follow-up e-mail discussions continuing through August 15, 2010. The recommendations in the two guidelines were discussed using a moderated group process, and formal votes were taken when necessary. The goal of this article is to present the results of the discussion and includes a set of consensus points agreed upon by both organizations. However, there are still areas of continuing disagreement. Additional research might help to better inform decisions about screening mammography and ultimately provide more effective patient care.
Formally approved ACP-ACR consensus points for screening mammography in average-risk women*
1. Screening mammography has been shown to decrease the number of deaths from breast cancer in women ages 40-74.
2. The benefits and harms associated with screening vary by age, and women will view these benefits and harms differently. Thus, all women should discuss the benefits and harms of breast cancer screening with their physician.
3. Breast cancer incidence increases steadily with age. There is no abrupt change in incidence at age 50. Additionally, the outcomes of screening (recall rates, biopsy recommendation rates, and cancer detection rates) also change steadily with increasing age, without any sudden change at the age of 50.
4. Younger women have a lower risk of breast cancer but more potential years of life saved by detection and successful treatment.
5. Since women over the age of 74 were not included in the randomized, controlled trials, there is no proof that screening saves lives in older women. Decisions about screening in this age group should be individualized and made between a woman and her physician.
6. The majority of breast cancers occur in women without major risk factors.
7. There are false-positive screening studies at all ages that result in women being recalled for additional evaluation that ultimately shows no evidence of cancer. With increasing age, there is a gradual decrease in the percentage of false positives as the incidence of breast cancer increases.
8. It is important to note that mammography does not find all cancers, and some cancers that are detected may not be found early enough to result in a cure. If a woman discovers a lump, even after having had a negative mammogram, she should bring it to her physician's attention. If a physician remains concerned about a clinically evident finding, even after a negative mammogram, the finding should be evaluated further.
9. The primary benefit of screening mammography is a reduction in mortality from breast cancer.
10. The potential harms associated with screening mammography include:
- transient discomfort from the study;
- recall for a false positive mammogram resulting in anxiety and inconvenience (the majority of these are resolved by additional mammographic views and/or ultrasound);
- the need for biopsy of a lesion that is ultimately proven to be benign; and
- treatment of a cancer that would not have become clinically significant. At present, we are unable to distinguish cancers that have lethal potential from those that do not, whether or not they are clinically evident or detected by screening mammography. Consequently, all women being evaluated for breast cancer, no matter how it was detected, should be informed that it is possible they may undergo treatment for a cancer that might not have lethal potential.
11. Third-party payers should cover screening mammography for all women ages 40 and above who elect to be screened.
*Approved by the ACP Board of Regents on February 10, 2011.
Approved by the ACR Board of Chancellors on May 14, 2011.