From the Director's Desk
Moving Beyond Mammography
In November 2009, the US Preventive Services Task Force (USPSTF) announced new recommended guidelines for mammography screening for women with normal risk of developing breast cancer.
They advise that:
- Women in their 40s of average risk for breast cancer should not routinely get mammograms
- Women who are between 50 and 74 should get mammograms every other year
- Doctors should discontinue teaching breast self-examination
The task force was unable to make recommendations for screening women older than 75 or for clinical breast examinations because the evidence was inconclusive. These recommendations have sparked a heated debate in the breast cancer community, although the controversy is not new.
Earlier Findings and Recommendations
In 2002, the USPSTF (an independent panel of experts in prevention and primary care that operates under the Agency for Healthcare Research and Quality) set women’s screening guidelines to every one to two years beginning at age 40, with the caveat that there was insufficient evidence to specify the optimal screening interval for women aged 40-49.
At the time, some groups (including the American Medical Association, the American College of Radiology and the American Cancer Society) supported the USPSTF recommendation, while other groups (including the American Academy of Family Physicians, the American College of Preventive Medicine and the Canadian Task Force on Preventive Health Care) recommended that average-risk women begin screening at 50 and that women 40-49 be counseled about the risks and benefits of mammography before deciding about screening.
Comparing Efficacy against Increased Harm
In 2009, the USPSTF panel (consisting of different members) analyzed the efficacy of different screening methods in reducing breast cancer mortality, but also factored the harms of overtreatment (including risks from scarring, radiation, and drug side effects) and psychological distress into their analysis. They reviewed the evidence from established studies of the risks and benefits of screening by film mammography, breast self-examination, clinical breast examination, digital mammography, and magnetic resonance imaging. They also used computer modeling to compare the expected outcomes using the different screening methods at different intervals.
The resulting analysis led the committee to conclude that as a general screening tool, the harms outweighed the benefits of mammography for screening pre-menopausal women. They observed that reduction in mortality in this age group was slightly less than in women screened post-menopausally, while the cumulative risk for a false positive mammography result was 56% after 10 mammography examinations compared to 21% to 49% for women in general. The findings have not caused professional or advocacy groups to shift their positions, but they have inspired the community to re-examine assumptions and values.
The Need for Better Technology
This debate arises because we are dealing with an imperfect technology that forces us to make tough choices. It is undeniable that mammography can catch breast cancer early enough to save an individual life. It is also undeniable that mammography has led to a great deal of anxiety, unnecessary biopsies, over-treatment, and has actually caused some cancers, particularly in women younger than 50. The true challenge to the CBCRP and researchers is to make the debate irrelevant by finding an accurate way to identify life threatening disease.
The CBCRP is meeting the challenge by investing in approaches that we hope will lead to a paradigm shift in how breast cancer is detected and diagnosed. The breakthrough may come in the development of new technology such as functional magnetic resonance imaging or volume breast ultrasound. Or it may come by identifying which biological markers, alone or in combination, can reliably distinguish harmless changes in the breast from dangerous ones.
Only by pursuing alternative approaches to detecting breast cancer will we be able to move beyond the quandary mammography presents and offer women clear guidance about when and how often to be screened for breast cancer.
