Who Should Get Mammograms?

There are lots of good reasons to try and follow a healthier diet—you lose weight, you feel good, but the main reason–to live a longer, happy productive life.  Sounds good, right?   And though it may sound deceptively easy, the devil is in the details.   Welcome to the NutritionFacts podcast. I’m your host Dr. Michael Greger. 

Today, we ask the question, “Who should get mammograms?”  Some women, all women, no women?  The guidelines for mammograms have been changing and none of the authorities seem to agree.  Should women start in their 40s, 50s? Every year, every other year?   Well, as it turns out, most women are just being told what to do, rather than being given the facts necessary to make a fully informed decision.  Here’s the story. 

“Selling [cancer] screening can be easy,” starts an editorial in the Journal of the National Cancer Institute. “Induce fear by exaggerating risk. [Then,] [o]ffer hope by exaggerating the benefit of screening. And, don’t mention harms [caused by the screening].” This ploy “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.

“Screening can lead to important benefits, but it can also lead to important harms.” And, so, that’s the big challenge: “conveying the counterintuitive idea that screening [doesn’t] always help—and can even be harmful.” Yet, “[s]urveys 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[s] to potential harms [may] deceptively [be] “buried [under] a euphoria of benefits.”

The cancer screening test that has been most carefully studied is mammograms. “In the past 50 years, more than 600,000 women have participated in 10 randomized trials… Given this extraordinary research effort, [it’s] ironic that [mammograms] continue…to be one of the most contentious issues within the medical community.” “There are few [things in medicine] that invoke more passion…than mammograms, with both sides, ironically, accusing the media of being in the opposite camp.

But, this contentiousness “is in itself instructive.” I mean, it should tell us something. “For context, “a [single study] involving fewer than 150 men who were followed for less than 2 years was sufficient to convince physicians of the value of treating severe [high blood pressure],” because the benefits were just so obvious; whereas after 10 trials, 600,000 women, the fact that we’re “still debating the…merits of [mammograms] 50 years later suggests that it’s “a close call” between the benefits and harms. But, that’s assuming people are weighing the pros and cons objectively. It may be worse than that, given the multibillion-dollar industries involved, from the mammogram-machine manufacturers to the radiologists that read them.

“Several organizations publish [contradictory] cancer screening recommendations.” Some say mammograms starting at age 40; others say 50. Some say every year; some say every other year, and some say women shouldn’t get them routinely at all. “There is increasing concern” that these disagreements may be arising from “both financial and emotional conflicts of interest.” People can get so invested in their position that they’ve staked out that it kind of clouds their judgement.

“Reasonable experts agree that the body of evidence suggests that there is some benefit to mammography… Although the benefits…have almost certainly been exaggerated, this does not mean that [mammograms don’t] save lives, or that women shouldn’t get [them].” The question is: do the benefits outweigh the risks? That’s a decision each woman has to make for themselves, but they can’t do that without knowing all the facts.

Women are so bombarded with information about mammograms, you’d think women would be “fairly knowledgeable” about it. “Yet nothing is farther from the truth.” Nine out of ten women surveyed “vastly overestimated the benefit[s],” 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 screening, thinking mammograms somehow help prevent you from getting breast cancer in the first place. This “raises doubts” about how well women are being informed. Sounds like “[w]omen are just being told what they should do, but without being given the facts necessary to make informed decisions…As a result of this 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.” So, they were like anti-educated by their doctors. And, the problem is that ‘these kinds of inaccurate and exaggerated perceptions” prevent women from making an “informed choice.”

“Misleading women, whether intentionally or unintentionally,…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 [just blindly] be selling screening. We should be giving people the numbers they need to decide for themselves.”  “The question of whether screening mammography does more harm than good has the potential to shake up the state of [our] medical knowledge [and] alter our views of ethical [medical] practice…The stakes are high in this discourse because women’s lives hang in the balance.”

When women are fully informed about the risks and benefits of mammograms, 70% may choose not to get screened.  But you may be in that 30%, and you have a right to decide for yourself.

“For nearly a century, public health organizations, professional associations, patient advocacy groups, academics, and clinicians largely viewed cancer screening as a simple, safe way to save lives.” But these days, even though we’re all looking at the same body of evidence, “[d]iffering interpretations about [the] benefits and harms of [mammograms] has led to conflicting recommendations…that range from intensive [annual] screening starting at age 40 to no [routine] screening at all [ever].” Currently, the four main groups in the U.S. “charged with making [mammogram] recommendations” each set contradictory guidelines. So, what’s a woman to do?

Well, the guidelines are based on “systematic reviews” of the evidence. “In the last 15 years, 50 [such] reviews…have been published,” but they don’t all reach the same conclusions. The question is, why? It turns out the conclusions of systematic reviews may have been influenced by competing conflicts of “interests of the authors.”

“[O]nly in health care [does] the same group that provides a service also [tell] us how valuable that service is and how much of it we need… We must [sadly] acknowledge that just as in any other profession or industry, self-interest is unavoidably at work…” In an analysis of more than a hundred papers, the “imbalance” in those that tended “to emphasize the major benefits of mammography…over its major harms [was] related to the authors’ affiliation.”

It may be no coincidence that all the expert panels that have come out against routine mammograms excluded radiologists, figuring those who depend on mammograms for their paycheck might be more likely to recommend them—to which mammogram proponents respond: “if you don’t have a conflict of interest, you[’re] probably [not doing it right],” accusing the breast cancer-screening panels of “inject[ing] their own biases.” “In this debate, there are armies of the faithful, and only a disappointing scattering of moderators and peacemakers.”

Some have even suggested that we shouldn’t even be talking about this in public, but “[s]uch paternalism assumes that women cannot decide for themselves whether the available evidence supports or refutes the case for mammography. Discouraging a discussion with women about the evidence for and against…[could be considered] more harmful for women’s health, not less, if doctors truly believe that patients should be active partners in making decisions about their [own body].”

Yeah, if you read the actual studies, you can see if the investigators declare any conflicts of interest. But, if you just hear about the studies second-hand, you may have no idea. Until the developers of screening guidelines emphasize “evidence over commercial or financial interests,” we all have to take personal responsibility to become “informed consumers.”

It would be nice to be able to just trust like cancer charities, but “[i]t is virtually impossible” for such organizations to remain strictly “evidence-based” when they must rely on keeping donors happy “for their very existence.”

To his credit, the Chief Medical Officer of the American Cancer Society said that “we need to be true to the science.” But, note this was him talking about prostate cancer screening. See, the American Cancer Society just straight up tells women to get mammograms, but for men, it leaves them to decide for themselves. They’re open about the prostate cancer-screening harms, but “[v]ery little transparent information about the harms of [mammograms] is provided…”

So, there’s this “double standard”; “women are encouraged” to just do it, “while men are advised to” weigh the pros and cons, “although the fundamental issues to consider are [actually] very similar” between the two tests. “The dissimilarity in how [organizations like the American Cancer Society] view” the patients’ role in decision making “couldn’t be clearer. Do [they] believe that men can handle uncertainties regarding screening tests…,” but that women might just get all “confused”? Men get to “make informed decisions” about their bodies, but women are merely “summoned.”

The bottom line is that there is “more than one right answer” to the question: “Should I be screened for breast cancer?”

Various health authorities offer clashing mammogram recommendations that range from annual mammograms starting at age 40 to eliminating routine mammograms altogether. Who should you trust?  A good place to start is the USPSTF, the U.S. Preventive Services Task Force, whose 2009 recommendations “ignited a firestorm” of controversy by recommending pushing back routine mammograms from age 40 to 50, and doing them every other year, instead of annually. This evoked “a swift and decidedly passionate condemnation from members of the public, the media, and [medicine].”

Most people have never even heard of the USPSTF, but it’s “considered the leading independent panel of [nongovernmental] experts” when it comes to prevention—considered the “gold standard for preventative care,” since they have a reputation of sticking more with the science, for example, “recommending against” teaching women to do breast self-exams. Why? Because it doesn’t appear to work. It was put to the test—hundreds of thousands of women randomized to do self-exams or not, and no benefit—in fact, only harms: doubling the number of women who had to get biopsies taken, but not actually shown to decrease the risk of getting breast cancer, or dying from breast cancer. It didn’t catch tumors in earlier stages.

Now, to be clear, they didn’t come out against breast self-examination, but “against teaching” women how to do them; reminding them to do them only appears to cause harm with no benefit. If you do discover an abnormality, then definitely tell your doctor, but telling women to get into the practice of looking seems to do more harm than good. Yet, most doctors continue to teach women to perform self-exams. But wait; it’s not been shown to help, and, in fact, has been shown to harm, so why do doctors keep doing it? Because that’s just what we’ve been telling women forever. So, there’s this medical inertia that may trump women’s health—even without a multibillion-dollar industry pushing for the practice to continue. Even without Big Business tipping the scales.

Now, consider mammograms. Billions of dollars of revenue every year from sticking with the status quo. Maybe the $7.8 billion spent annually on mammograms “might be better spent on something else.” Of course, “[o]ne person’s cost is another person’s income.” These billions of extra dollars from the status quo may “best explain the organized resistance to the…USPSTF panel [conclusions].” For example, breast radiologists denounced the panel, “implying that the panel members were guilty of a callous disregard for the life and well-being of women,” all while the American College of Radiology is receiving millions of dollars of donations from mammogram machine manufacturers.

Yeah, but in the case of self-exams, it was put to the test, and the science was clear. It’s a no-brainer that harms outweigh the benefits, when apparently there are no benefits. And, the same appears to be the case with starting mammograms at age 40. It was put to the test to specifically address “the population-wide efficacy of mammography screening starting at..age…40…,” and it started out looking like it might help, but ultimately failed to show any benefit in terms of lowering one’s risk of dying from breast cancer. Instead, they just found harms, so-called “overdiagnosis”—all the chemo, radiation, and surgery from the detections of what looked like cancer, but may have never caused any problems had they never been picked up.

So, it may have just resulted in like unnecessary mastectomies. Yet, when the USPSTF tried to explain that again in their 2016 recommendations, the firestorm was reignited, with full-page ads taken out in major papers asking, “Which of our mothers, wives, daughters, and sisters would it be OK to lose?” But, that misrepresents the science—disrespecting women, rather than saving their lives. It’s time to “douse the flames,” “clear the smoke so that we can clearly see what the evidence shows…”

Evidence, schmevidence, said Congress, who snuck in some language to interpret any reference to “current” USPSTF breast cancer-screening recommendations to mean those issued “’before 2009’—in other words, its 2002 recommendations” that recommended annual mammograms starting age 40. “Essentially, Congress is requiring health insurers to ignore modern scientific assessments, and instead use [a 15]-year-old guidance.” “Although many women’s health advocates applauded the congressional mandate, it [could be viewed as undermining] women’s rights to make informed decisions based on the best scientific evidence.”

The same thing happened 20 years ago, when “a National Cancer Institute…consensus panel arrived at [the same conclusion],” but the Senate voted unanimously “to ignore” them. The number one killer of women is heart disease. Why not focus our billions on more effective interventions? “Since health care dollars are limited,” maybe we could be doing more for women’s health.

But hey, it could have been worse. The original bill “would have denied funding for any future USPSTF mammography recommendation[s],” period. And “[s]ome members of Congress [even proposed] to alter the Task Force’s composition to include ‘stakeholders from the [mammogram machine manufacturers],” so they can play a more direct role in influencing policy.

To see any graphs, charts, graphics, images or studies mentioned here, please go to the Nutrition Facts podcast landing page. There, you’ll find all the detailed information you need, plus links to all of the sources we cite for each of these topics.

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Thanks for listening to Nutrition Facts. I’m Dr. Michael Greger.

This is just an approximation of the audio content, contributed by Allyson Burnett.