Thursday, November 19, 2009

Mammography Screening Myths Exposed

The US Preventive Services Task Force (USPSTF) released "new" mammogram guidelines this week. The guidelines have received major backlash from the American Cancer Society and many cancer survivors.

Below is are some of the mammography screening myths floating around:

Myth #1. These are new guidelines
Ok, so these guidelines are "new" for USPSTF (although they look a lot like older USPSTF guidelines). However, the guidelines are now very similar to recommendations of health organizations in other countries (the Vancouver Sun lists mammography screening guidelines from England, Austria, Finland, France and more). In fact, I don't know any organization other than the American Cancer Society and National Cancer Institute that recommends yearly mammograms for women aged 40-49.  Biennial screening (screening once every two years) is reasoned because of potential harm that follows a false positive test (meaning you get a positive mammography result, but you don't really have cancer). It can lead to stress, anxiety, painful and potentially harmful biopsies (no invasive procedure is 100% safe even if its worth doing on balance).

Even under the "old" guidelines, the USPSTF was hesitant to recommend annual screening for women under age 50 because of the negligible benefit that they found at a population level. Instead, they recommended screening every 1-2 years, to be determined by a woman in conversation with her doctor.

Myth #2. The guidelines will lead to a of rationing care, USPSTF might as well be called a "death panel"
The latest on Twitter suggests that, at least for now, insurance companies will "preserve mammogram coverage for younger women" (@LizSzabo). The New York Times also reports that insurance companies will continue to cover mammography screening. I'm sure coverage differs plan by plan to begin with, but it probably puts many women (including myself) at ease. With mammography technology so widespread in this country, I don't see a need for rationing mammograms, if anything a greater demand is still needed! Perhaps someone who has been through the experience can share whether it takes as long to get a mammogram as it does a primary care appointment!

Myth #3. Women who follow the guidelines will not have breast cancer caught in time
This gets complicated. Unfortunately, I haven't heard any estimates of how many women this might negatively affect, so my response will focus on the theory behind the recommendations. The USPSTF reviews published scientific literature that studies the probability of survival for women who receive mammograms. They look at clinical trials, the potential harms of screening, and they consider how the desired outcomes may be different among women of different ages. Epidemiological (i.e. population-based health research) studies are used to guide the recommendations, because they do not apply only to an individual woman, but to the entire US population. A woman who has breast cancer caught at 45 and shares a compelling story on the need for mammography screening of all women at that age does not represent the entire female population in the US. Basing population-level recommendations on individuals' anecdotes is unwise and can lead to very ineffective policies.

So what should you do?
Women who are at risk of breast cancer should absolutely take advantage of early screening (prior to 50). However, many more women get breast cancer than those labeled "at risk." It really is, and always should be, a decision that is made between you and your doctor. With many conflicting recommendations still out there, have that discussion and make your own decision. And be ready for the roller coaster that might await. The roller coaster may save your life.

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