Fewer Than One in Ten Informed About Most Serious Downside of Mammograms

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What do nine in ten women say they were never told about mammograms, even though they thought they had the right to know?

“Fueled by economic conflicts of interest”—with the multibillion-dollar mammogram industry—“and good intentions…many women [are] being given diagnoses of breast cancer that they did not need, producing unwarranted fear and psychological stress and exposing them to treatment that can only harm them.” Treatment they don’t need. As I discuss in my video Women Deserve to Know the Truth About Mammograms, this is the problem of overdiagnosis, “the detection of pseudo disease” or abnormalities picked up at mammogram screening that look like cancer under the microscope. So, you’re diagnosed with cancer and undergo treatment, but, all along, it was just pseudo disease that never would have actually progressed to cause symptoms. The “human costs” include mastectomies and even deaths. In fact, the chance of a woman benefiting from mammograms may be “ten times smaller than the risk that she may experience serious harm in terms of overdiagnosis.” 

“How many would elect to be screened [by mammogram] if they knew that for every one woman who is notionally saved by early detection, anywhere from 2 to 10 otherwise healthy women are being turned into breast cancer patients?” Well, first, are physicians even telling patients about the possibility of overdiagnosis? After all, “it is now recognized as the most serious downside” of mammogram screening. When hundreds of women were asked, fewer than one out of ten said they had been informed about it. And when they were told about the possibility of overdiagnosis, a little more than half said they wouldn’t agree to screening if it resulted in “more than 1 overtreated person per 1 life saved from death due to cancer.” “Wow. That implies that millions of Americans might not choose to be screened if they knew the whole story; however, most”—90 percent, in fact—“do not.” 

Most “women are aware about false-positives results and seem to view them as an acceptable consequence of screening mammography. In contrast, most women were unaware that screening can detect cancers that may never progress” and that what they don’t know could potentially even kill them. So, when considering the pros and cons of mammograms, it would be good to consider total mortality. Can the screening help you live longer on average? In fact, mammography “has not reduced total mortality, and it is therefore misleading to claim that ‘screening saves lives.’” 

Theoretically, routine mammograms should increase a nonsmoking 50-year-old woman’s “overall survival chance from 96.3% to 97.1% over 10 years.” However, “[t]hese statistics disregard deaths from overdiagnosis.” This includes deaths from the unnecessary “radiotherapy [radiation] and chemotherapy and thus increased mortality from heart disease and other malignancies [cancers] that may entirely outweigh the benefit in terms of reduced breast cancer mortality.” 

You can’t irradiate the breast without exposing the rest of your chest, including your heart and lungs, to radiation. This explains why breast cancer survivors can end up with “significant and marked impairment in cardiopulmonary [heart-lung] function over the entire continuum of disease.” “Radiation therapy as a treatment for breast cancer actually increases deaths from heart disease by more than 25% and from lung cancer by nearly 80%—a big risk for a woman who may not need to take it.” We might accept that risk if we were beating back a deadly cancer, but the “main effect of screening is to produce patients with breast cancer from among healthy women who would have remained free of breast disease for the rest of their lives had they not undergone screening.” That is, some women are being turned into cancer patients for whom treatment offers zero benefit. “Compelling data” suggest that “most overdiagnosed tumours would have regressed spontaneously without treatment.” 

“Still, individuals who have had a cancer detected and then removed are likely to feel that their life was saved,” but it’s perhaps ten times likelier that their lives were seriously harmed, not saved, and ten times likelier they were told they had a cancer that could kill them, but they really didn’t. Imagine being corralled into the operating room for surgery you didn’t need. Think about every doctor’s appointment and every sleepless night—all completely unnecessary—and yet you become mammograms’ greatest advocate, thinking screenings saved your life. That’s the crazy thing about mammograms and about PSA testing for prostate cancer, too. The people who are the most harmed are the ones who claim the greatest benefit.

“Overdiagnosis creates a powerful cycle…for more overdiagnosis because an ever increasing proportion of the population knows someone—a friend, a family member, an acquaintance, or a celebrity—who ‘owes their life’ to early cancer detection.” So, the worse the test is and the more overdiagnosis it causes, the more popular it becomes. Indeed, the “popularity paradox of screening” is that the more mammograms harm women, the better women seem to think they work, and the more breasts that are surgically removed completely unnecessarily, the more women swear by it.

Billions of dollars may be being wasted “for false-positive mammograms and breast cancer overdiagnosis” that could be spent on doing more for women’s health, but it’s the human costs that concern me, considering that the harms from breast cancer screening may outweigh the benefits when you include deaths caused by treatment. Based on some best- and worst-case scenario estimates, for every ten thousand women invited for ten years of mammogram screening, three to four breast cancer deaths may be avoided at the cost of around two to nine deaths from the long-term toxicity of unnecessary radiation treatments. Yet, only one in ten women undergoing mammography said they were ever told about overdiagnosis, even though nine out of ten thought they had the right to know.

Overdiagnosis is not easy to discuss. It’s a sensitive issue, but “just because communicating with patients will be difficult does not mean that we should not tackle this problem. Informed women deserve no less when deciding about breast cancer screening.” We have an ethical responsibility to let them know.

Women deserve to know the whole truth about mammograms so they can make up their own minds. I am not opposed to mammograms. I am opposed to the patronizing attitude that women should be pressured into getting them without being fully informed about the benefits and risks. Some women will still choose to get them, but others will not. It’s up to them to decide. 

KEY TAKEAWAYS

  • Overdiagnosis—the diagnosis and treatment of breast cancer that never would have even threatened the woman’s health—has resulted in many unnecessary surgeries, radiation regimens, and chemotherapy treatments, along with unwarranted fear and psychological stress.
  • The chance of a woman benefiting from mammograms may be “ten times smaller than the risk that she may experience serious harm in terms of overdiagnosis.”
  • How much do women know about the possibility of overdiagnosis? Fewer than one in ten said they had been informed about it, and more than half said that, had they known about the possibility of overdiagnosis, they wouldn’t agree to screening if it resulted in “more than 1 overtreated person per 1 life saved from death due to cancer.”
  • Although most are aware of false-positive results and accept them as a consequence of mammograms, most did not know that screening can detect cancers that may never progress at all.
  • Unnecessary radiation resulting from overdiagnosis exposes more than just the breast. The chest, including heart and lungs, are exposed, which is why breast cancer survivors may have significantly impaired cardiopulmonary function. Indeed, radiation therapy for breast cancer treatment increases deaths from heart disease by more than 25 percent and from lung cancer by nearly 80 percent.
  • With overdiagnosis, it is increasingly common to know someone who “owes their life” to early detection, so screening becomes even more popular.
  • The harms from breast cancer screening may outweigh any benefits. For every ten thousand women invited for ten years of mammogram screening, three to four breast cancer deaths may be avoided at the cost of around two to nine deaths from the long-term toxicity of unnecessary radiation treatments.
  • Only one in ten women undergoing mammography said they were ever informed about overdiagnosis, even though nine out of ten thought they had the right to know.

Check out the other videos in my 14-part series on mammograms:

For more on breast cancer, see my videos Oxidized Cholesterol 27HC May Explain Three Breast Cancer Mysteries, Eggs and Breast Cancer and Flashback Friday: Can Flax Seeds Help Prevent Breast Cancer?

I was able to cover colon cancer screening in just one video. If you missed it, see Should We All Get Colonoscopies Starting at Age 50?.

Also on the topic of medical screenings, check out Flashback Friday: Worth Getting an Annual Health Check-Up and Physical Exam?, Is It Worth Getting Annual Health Check-Ups? and Is It Worth Getting an Annual Physical Exam?.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

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