Why Patients Aren’t Informed About Mammograms

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“In the…mammography wars, rational thinking can be easily lost.” Yes, mammograms are big business, bringing in about seven billion dollars a year. But, “[i]t would be [a bit] too…cynical to believe that [the pushback from mammogram critics] stems only from [the] self-interest of radiologists [and breast] surgeons,…whose daily bread depends on the continuation of [routine mammogram] screening. It just makes intuitive sense that mammograms should work. But, that’s why we have science—so we can put things to the test. “We owe it to [our patient]s to be ‘evidence-based’ rather than ‘faith-based.'” “[They] deserve [an] objective analysis of the data.”

“[W]e have done a dismal job of accurately informing the public,” and the question is: why? Well, one reason is that the doctors themselves aren’t informed. “For example, a survey of…radiologists found that 96% overestimated a [middle-aged] woman’s risk of breast cancer.” In one sneaky study, researchers called up gynecologists, and pretended to be a concerned family member asking for a phone consultation about the benefits and harms of mammograms. “Although all [the] gynecologists appeared motivated and concerned with sufficiently answering our questions, they [simply appeared to lack the] information as well as knowledge of how to communicate information on medical risk.”

“When Doctors Meet Numbers.” “We cannot take for granted the ability of physicians to understand and interpret [data and…] use it to the best advantage of the patient.” “[A]n educational blind spot” for physicians, identified more than 80 years ago. In this study, for example, 151 practicing physicians were asked a series of multiple choice and true-and-false questions to gauge their practical understanding of some key concepts. And, they failed miserably: only got 55% correct, only about 20% more than they would have gotten just randomly guessing.

If doctors don’t understand health statistics, how can they possibly counsel patients properly? There was a famous study in which a hundred physicians were asked what the chances were of a woman actually having breast cancer if her mammogram came back positive. They gave them all the numbers so they could do the math, and 95 out of 100 not only got it wrong, but spectacularly wrong: off by a thousand percent.

Even doctors at Harvard had a problem. “…[F]aculty, staff, and students at Harvard Medical School” were asked a simple question, and 82% got it wrong. That was a few decades ago, though. In an updated survey in Boston, only 77% got it wrong, an average of about 3,000% off, demonstrating medicine’s continued discomfort with math.

“Only 12% of [thousands of OB-GYN] residents were able to correctly answer 2 simple questions on medical statistics.” “What will the uninformed 88% of these residents say when their first patient asks about her chance of truly having breast cancer given a positive mammogram?” And, what’s particularly frightening is that in some studies, “those [doctors] most confident in their estimates were furthest away from the correct response.” So, they didn’t even know that they didn’t know. “All of these studies document the same phenomenon: A considerable number of physicians are statistically illiterate, that is, they do not understand the statistics of their own discipline.”

So, when physicians say they don’t have time to fully inform patients about the benefits and harms of a test, maybe that’s a good thing—if they don’t know what they’re talking about! Instead, they may just talk about the benefits, and skip the whole harms part. And so, we shouldn’t be surprised when nine out of 10 women say, “Harms from mammograms? What harms?” while often greatly overestimating the benefits—whereas, “[i]n fact, the benefits and harms [may be] so evenly balanced that maybe we should just inform women, and let them make up their own minds. But, that’s not what you hear from ad campaigns. They just tell women to do it, overstating the benefits, sometimes ignoring harms altogether, using persuasion instead of education—”fear, guilt,” whatever it takes.

“[I]t is easy to ‘sell’ screening: just magnify the benefit, minimize the [harms],…keep the actual numbers [under wraps].” I mean, studies have randomized hundreds of thousands of women to get mammograms, or not to put it to the test. What’s the point if we’re not going to share the results? “We spend billions on [these] clinical studies, but fail to ensure that patients and physicians are communicated the results [in a] transparent…[manner]. Maybe women should “tear up the pink ribbons and campaign for honest information.” How else can women “make informed decisions”?

Instead, we get hospitals putting on like mammogram parties. Maybe, in addition to the appetizers, they should serve women “balanced information…to chew on” as well.

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Motion graphics by Avocado Video

• breast cancer
• breast cancer survival
• cancer
• Harvard
• industry influence
• lifespan
• longevity
• mammograms
• mortality
• surgery
• women's health