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Behind Today’s Confusing Mammogram Screening Guidelines


As a breast-imaging radiologist, I often see firsthand the confusion that women face regarding when – or if – they should get screening mammograms. Over the last few years, organizations that women trust for guidance about when and how often to be screened have released or updated recommendations that vary widely. The resulting confusion may be leading some women to wonder whether mammograms are even effective at preventing deaths from breast cancer since no one seems to agree on key details.

While the Society of Breast Imaging recommends that women start at 40 and continue getting mammograms yearly, the American Cancer Society (ACS) says women should get annual screenings at 45 and biennially starting at 55. A third organization, the U.S. Preventative Task Force (USPTF) updated its guidelines earlier this month, advising women of average cancer risk to get screened every other year between ages 50-74 while high-risk women should begin at 40. Three major players on the front lines of the fight to detect best cancer, three different sets of guidelines. No wonder so many women are scratching their heads, puzzled about whose advice to follow.

The good news is that all three groups agree on the most important point: Beginning mammogram screenings at 40 and continuing each year (the Society of Breast Imaging’s recommendation) saves the most lives. The disagreement centers on how to balance the benefit of mammograms with the harm. It’s not the mammograms themselves that can be harmful — all three organizations agree that the impact of radiation is negligible. The harm, say the USPTF and ACS, is about what happens after a woman is screened.

About 10 in 100 women who go in for a screening mammogram will need to be called back for additional mammographic pictures or an ultrasound. Of those 10, six will be told at the time of the additional imaging that everything is fine. The more mammograms a patient acquires over her lifetime, the more likely she is to be called back at some point for additional imaging.

The USPTF warns that further screening and the potential for “false positives” — a term that in this case simply means that more imaging is necessary — causes inconvenience and psychological harms in the form of anxiety that outweighs the benefit (life saved) of being tested in the 40s, or being tested every year after 50.

While it’s true that many women experience anxiety when they hear they need additional imaging, research shows that this anxiety is temporary and that most women will choose to tolerate the risk of possible temporary anxiety in exchange for the potential to save their life from getting annual mammograms.

Another reason that the USPTF and ACS tell women that they don’t need a mammogram yearly starting at 40 is because of the potential for overtreatment of cancers that may never kill you anyway. While it’s true that some cancers may never spread, we haven’t yet reached a point in medicine where we’re able to predict which cancers are dangerous (most) and which aren’t (rare). Very few people are willing to accept the risk of allowing a cancer that may be viewed as less threatening to have the opportunity to wreak havoc by simply ignoring it. The USPTF does not mention the harm of not screening women annually in their 40’s of potential lives lost.

A further disagreement surrounds the suggestion by the USPTF and ACS to consider a woman’s underlying risk for breast cancer in deciding when to start screening. This suggestion could be extremely harmful because it may lead women with no history of breast cancer in their family or other risk factors to believe that they don’t need a mammogram. In fact, 75% of women diagnosed with breast cancer in their 40’s have no special risk factors and fall in the average-risk group. By advising average-risk women to wait until 45 (ACS) or 50 (USPTF), we are only catching a fraction of the breast cancer in women between ages 40 and the recommended start age.

The bottom line is this: Women should be emboldened to make an informed decision that works best for them. The facts are the facts: Getting screened every year at 40 will save the most lives. If the potential for anxiety and overtreatment outweighs your concern of a breast cancer diagnosis, then waiting until 45 or 50 may be the best option for you. But it’s important that women are aware that they’re trading the chance to find out that they have cancer at an early stage when it can be most effectively treated, for relief from anxiety and the theoretical potential of overtreatment.

Phoebe Freer is an associate professor of radiology at the Huntsman Cancer Institute at the University of Utah.