Image Credit: National Cancer Institute / Unsplash. This image has been modified.

90% of Women Appear Misinformed About Mammograms 

Most women are just being told what to do, rather than being given the facts needed to make a fully informed decision.  

“Selling cancer screening can be easy,” begins an editorial in the Journal of the National Cancer InstituteInduce fear by exaggerating risk. Offer hope by exaggerating the benefit of screening. And don’t mention harms [caused by the screening]It is especially easy with cancer—no diagnosis is more dreaded. And, we all know the mantra: early detection is the best protection. Doubt it, and someone may suggest you need your head examined.” And they are not exaggerating, as you can see for yourself at 0:37 in my video Nine out of Ten Women Misinformed About Mammogramswhen I show an American Cancer Society pamphlet that actually warns women, “If you haven’t had a mammogram, you need more than your breasts examined.” 

Screening can lead to important benefits, but it can also lead to important harms, continues the editorial. “A big challenge is conveying the counterintuitive idea that screening does not always help—and can even be harmful. Surveys have shown that most people believe that cancer screening is almost always a good idea and few believe harm [is even] possible.” In patient education materials, passing reference to potential harms is deceptively buried in a euphoria of benefits.”  

The cancer screening test that has been studied most carefully is the mammogramIn the past 50 years, more than 600,000 women have participated in 10 randomized trials, each involving approximately 10 years of follow-up. Given this extraordinary research effort, it is ironic that screening mammography continues to be one of the most contentious issues within the medical community.” Indeed, in medicine, there are few fields that invoke more passionthan the question of screening women for the detection of an earlier, more curable stage of breast cancer.” Ironically, both sides accuse the media of being in the opposite camp. 

This contentiousness, however, is in itself instructive. It should tell us something. For context, one trial involving fewer than 150 men who were followed for less than 2 years was sufficient to convince physicians of the value of treating severe hypertension.” The benefits of treatment were just so obvious. In contrast, the fact that we’re still debating the merits of mammograms 50 years later, even after 10 trials with 600,000 women, suggests that the test is surely a close call, a delicate balance between modest benefit and modest harm. However, that assumes people are weighing the pros and cons objectively. Given the multibilliondollar industries involvedfrom the mammogram machine manufacturers to the radiologists who read themit may be worse than that. 

Several organizations publish contradictory cancer screening recommendations. Some recommend mammograms starting at age 40 while others say 50. Some say every year, some say every other year, and some recommend that women shouldn’t get them routinely at all. There is increasing concern about both financial and emotional conflicts of interest interfering in the generation of guidelines. People can get so invested in the position they’ve staked out that it may cloud their judgement. 

Reasonable experts agree that the body of evidence suggests that there is some benefit to mammography among women aged 40 yearsAlthough the benefits of mammography screening have certainly been exaggerated, this does not mean that it does not save lives or that women should not get it. The question is, do the benefits outweigh the risks? That’s a decision each woman has to make for herself, but she can’t do that without knowing all the facts.  

Women are so bombarded with information about mammograms, you’d think they would be fairly knowledgeable about them. “Yet nothing is farther from the truth...” Nine out of 10 women surveyed vastly overestimated the benefits of mammograms or had no idea. It’s not the women’s fault, though. They’re obviously being misinformed by the system. Most American women didn’t even appear to understand the basic concept of mammography screening and “believed that screening prevents or reduces the risk of contracting breast cancer in the first place. This raises doubts about how well women are being informed. It sounds like women are told what they should do, but without being given the facts necessary to make informed decisionsAs a result of paternalism and pink ribbon culture, almost all women have a false impression of the benefit of mammography screening...Most surprisingly, those who frequently consulted their physicians and health pamphlets were slightly worse informed.” It’s as if they were antieducated by their doctors!  

The problem is that these kinds of inaccurate and exaggerated perceptions of the benefit of screening” prevent women from making an informed choice. “Misleading women, whether intentionally or unintentionally, about the benefit of mammography screening is a serious issue. All of those in the business of informing women about screening should recall that medical systems are for patients, not the other way around.”  

We should not be selling screening. We should be giving people the numbers they need to decide for themselves.” 

That’s exactly why I wanted to take on this contentious topic The question of whether screening mammography does more harm than good has the potential to shake up the state of medical knowledge, alter our views of ethical practice, and alter our application of screening principles. The stakes are high in this discourse because women’s lives hang in the balance.”  


  • The mammogram is the most carefully studied of all cancer screening tests, yet it is among the most contentious issues in medicine today.
  • To put it into perspective: A single trial with less than 150 men followed for less than two years sufficiently convinced doctors to the value of treating severe hypertension, whereas mammograms have been debated for 50 years—and continue to be debated—even after ten trials with 600,000 women.
  • Guidelines vary, and cancer screening recommendations may be contradictory. As well, benefits of mammography screening may be exaggerated.
  • Ninety percent of women surveyed vastly overestimated the benefits of mammograms or had no idea, and most American women did not appear to understand the screening’ basic concept and believed mammography screening “prevents or reduces the risk of contracting breast cancer.”
  • Are women being misinformed, whether intentionally or not?  “As a result of paternalism and pink ribbon culture, almost all women have a false impression of the benefit of mammography screening…Most surprisingly, those who frequently consulted their physicians and health pamphlets were slightly worse informed.” 
  • Screening can lead to benefits as well as harms, so people should be given the facts to be able to make fully informed decisions rather than be told what to do or misled by those who may profit from the procedures.

This is the first in a 14-part series on mammograms. There’s just so much confusion, combined with the corrupting commercial interests of a billiondollar industry. As with any important health decision, everyone should be fully informed of the risks and benefits, and make up their own mind about their own bodies. This is why I created this series, which includes 

For more on breast cancer, see my videos:

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

Also on the topic of medical screenings, check out 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: 


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

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