Mammography Screening Recommendations:
Wading through the recent confusion
By Jill C. Wilkens M.D.
Breast cancer is the most common cancer among women in the United States next to skin cancer. It is the second leading cause of cancer deaths, followed by lung cancer, among U.S. women. According to the American Cancer Society (ACS), this year approximately 207,090 new cases of invasive breast cancer will be diagnosed, and 39,840 women will die from this disease. The chance of a woman developing invasive breast cancer sometime in her life is slightly less than 1 in 8.
Early detection with mammography is credited for the steady decline in the breast cancer death rate in women age 50 and younger. In fact, since 1990, the death rate in that same age group has declined 3.2% annually, according to the ACS.
Why the recent confusion about breast cancer recommendations?
Breast cancer screening has come under recent scrutiny. A controversial study cited the potential risks of screening women under the age of 50. The research found these women were more likely to be called back for more testing or undergo unnecessary biopsies.
On November 16, 2009, the US Preventive Services Task Force (USPSTF) released breast cancer screening recommendations based on this research, sparking controversy and intense media coverage. This task force, an independent panel of experts in prevention and evidence-based medicine composed of primary care providers (such as internists, pediatricians, family physicians, gynecologists/obstetricians, nurses, and health behavior specialists) recommended against mammography for women aged 40 to 49 years, despite evidence that mammograms save lives. They also advised against women examining their own breasts, a method by which many breast cancers are detected. Although the relative risk reduction rates associated with routine mammography in women aged 40 to 49 and 50 to 59 are similar (15% vs 14%, respectively), the USPSTF indicated that the absolute risk reduction is greater for women in the latter age group because breast cancer more commonly occurs in this age group; therefore, they concluded that for women in the younger age-group, the benefits did not outweigh the harms. The harms indicated by the task force included increased anxiety, radiation exposure, and inconvenience due to false positives. The USPSTF’s change in recommendations was largely attributed to a randomized study that showed physicians would have to screen 1,904 women in the 40 to 49 age range to prevent 1 cancer death, compared to 1,339 women over age 50. The data projects that starting mammograms at age 40 prevent one additional death but also leads to 470 false alarms for every 1,000 women screened. Continuing mammograms from age 74-79 prevent three additional deaths. As a result of their research, the USPSTF panel recommended the following new guidelines:
- Women receive their first mammogram starting at age 50.
- Women receive a mammogram every two years.
- Women stop mammograms after age 74.
- Women no longer perform breast self-exams.
- To summarize, the task force is stating that mammography between ages 40-49 and after 74 saves lives, just not enough of them. (Essentially, saving 1 life in 1000 in the 40-49 age group is not worth screening this age group). Of course, if YOUR life is the one that is saved, you will probably feel much differently about this issue.
- The task force wants to extend the time between mammograms from once a year to every two years. This may pose little risk for those women with indolent, slow-growing tumors, but what if YOUR tumor is a faster more aggressive type?
- The task force advises against women performing self-breast exams (SBE). However, women who are aware of how their breasts normally look and feel can detect subtle changes between yearly mammograms and/or clinical breast exams. SBE is an easy, inexpensive adjunct to the screening process. In fact, many breast cancers have been discovered by women, themselves. It would be unfortunate to eliminate such a simple method of early detection that could affect a positive outcome for YOU.
There were several limitations to the research conducted by the USPSTF, including a failure to adequately account for the impact of digital mammography and breast MRI. There was a lack of studies performed in much older women and insufficient data was obtained on the value of clinical breast exams. Another shortcoming was the skewed patient selection in that only women who were not at increased risk of having breast cancer were studied.
After careful consideration of the findings, several notable organizations, as well as many of our nation’s highly respected hospitals are in opposition to the USPSTF’s new mammographic screening recommendations. These include the following:
- ACS (American Cancer Society)
- American College of Radiology
- American College of Obstetrics and Gynecology
- American College of Surgeons
- American Society of Breast Imaging
- American Society of Breast Disease
- American Society of Clinical Oncology
- Mayo Clinic
- M.D. Anderson (Cancer Center)
The president of the American Society of Breast Imaging, W. Phil Evans, M.D. FACR commented:
“The USPSTF recommendations are a step backward and represent significant harm to women’s health. To tell women they should not get regular mammograms starting at 40 when this approach has overwhelmingly been shown to save lives is shocking. At least 40% of the lives saved by mammographic screening are of women aged 40-49. These recommendations are inconsistent with current science and apparently have been developed in an attempt to reduce costs. Unfortunately, many women may pay for this unsound approach with their lives.”
These organizations maintain that women should continue to follow these guidelines set forth by the American Cancer Society:
- Women receive an annual mammogram beginning at age 40.
- Women in their 20s and 30s get a breast exam about every three years.
- Women at higher risk of breast cancer because of family history or other factors talk to their doctor about when to start screening and what other tests they may need.
- Women continue with mammography every year if they are healthy.
- Women, starting in their 20s, learn how to conduct a breast self-exam and conduct a breast self-exam every month.
Mammography may not be a perfect screening tool, but it is the best one we have. The radiation dose from mammography is extremely low and continues to fall. The amount of radiation a mammogram exposes a woman to (0.3 mSv of radiation) is one-tenth of the dose a person receives each year from normal cosmic background radiation in our environment. The other “harms” cited by the task force, such as increased anxiety and inconvenience due to false positives are arguably a small price to pay for potentially life-saving breast surveillance at a younger age.
Daniel B. Kopans M.D., of Massachusetts General Hospital and one of the world’s leading experts on breast cancer detection and diagnosis, said “Screening has resulted in a 30% decrease in breast cancer deaths since the early 1990s when mammography began gaining popularity. Current American Cancer Society guidelines [recommending annual mammography for women starting at age 40] have been shown to save lives. The Task Force, by its own admission, said women will lose their lives. That doesn’t seem to be much of a choice.”
Progressive Radiology, in conjunction with the American College of Radiology, endorses the ACS guidelines. We are committed to the fight against breast cancer. We recognize that every woman’s breast cancer risks and individual needs are unique and therefore we advise that each woman consults with her medical provider to assist her with her own breast health screening recommendations.