Clinical practice guidelines vs. routine screening mammograms

When you need medical help, your doctor and other health care providers may be faced with difficult decisions and considerable uncertainty. So they rely on the scientific literature in addition to their own knowledge, experience, and patient preferences to inform these decisions.

And they also consider clinical practice guidelines, which are published recommendations intended to optimize patient care. But in a New York Times piece last month, Ronen Avraham, a professor at the University of Texas School of Law, observed that these clinical practice guidelines often conflict with one another.

Recommendations for when and how frequently women need mammograms, for instance, notoriously vary depending on which group is giving them.

He writes, for example:

“When doctors follow good guidelines, they are less likely to order too many or too few tests, or to prescribe the wrong treatment. But current clinical practice guidelines, written by either non-profit medical groups and for-profit insurance companies, are not good enough.

“In addition, there are conflicts of interest. Guidelines produced by insurance companies sometimes put their interests first. Malpractice insurers, for example, may recommend yearly mammograms, even if they are not necessary, because they bear the costs of lawsuits for late diagnoses of breast cancer — but not the costs or health risks of the extra mammograms.

“Moreover, the non-profit groups behind many other guidelines have traditionally depended on pharmaceutical and medical device companies to finance their work.”

Last year, the Council of Medical Specialty Societies in the U.S. issued a new code of conduct seeking to stop these industries from sponsoring the development of guidelines, but according to Ronen Avraham, there are still too many loopholes, and thousands of older guidelines produced before the reform are still in circulation – and are being followed by your doctors.

Here in Canada, the Canadian Medical Association’s Quality Of Care program cites over 40 organizations directly involved in guideline development.

Most troubling of all, Avraham wrote, is that the groups behind writing the clinical practice guidelines bear no liability for producing bad ones.

“No matter how poor the care these guidelines prescribe, it is the doctors who depend on them who are punished.”

And conflicts of interest are widespread. Researchers have found that more than half of the doctors who wrote key clinical practice guidelines in cardiology had financial ties to medical device and drug companies that stood to benefit from those guidelines, reports investigative journalist Alison Bass, author of the book Side Effects.

“This  study, published in the journal Archives of Internal Medicine, raises serious questions about the reliability of such clinical guidelines in treating heart disease. More than half of the doctors who wrote clinical practice guidelines in cardiology between 2004 and 2008 served as promotional speakers on behalf of industry, and a substantial number actually held stock in companies affected by the guidelines they wrote.”

She quotes Cleveland Clinic cardiologist Dr. Stephen Nissen, who said of this study:

“No conceivable logic can defend the practice of including promotional speakers and stockholders on clinical practice guideline writing committees. Physicians paid to serve on drug company speaker’s bureaus essentially become temporary employees of industry, whose duty is the promotion of the company’s products.”

Even more worrisome, says Alison Bass, this study found that the chairs of these guideline writing committees are significantly more likely (81%) than committee members (55%) to have a potential conflict of interest with industry.

And consider those controversial clinical practice guidelines around mammography to screen for early evidence of breast cancer.

In November 2009, the U.S. Preventative Services Task Force chaired by Dr. Ned Calonge recommended removal of its long-standing recommendation that women ages 40-49 receive regular mammography screening. The task force panel’s decision was based on “cold, hard science”, Dr. Calonge explained.

Our recommendation was evidence-based. Existing literature does not support the use of routine screening in this age group, meaning that the test carries small net benefit and should not be used routinely.”

Without screening, 3.5 out of every 1,000 women ages 40 to 49 will die of breast cancer in the next 10 years; regular mammography can reduce that number to three. The task force panel calculated that to save one life among women in this age group, 1,900 women must be screened annually for 10 years. The other 1,899 women, they determined, will receive no benefit from mammography over that period, though they will field 1,330 call-backs for reassessment and 665 breast biopsies, and eight of them will be diagnosed with cancers whose prognosis will not be altered by detection via mammogram – either because they would never become dangerous or because they are so aggressive that there’s little to be done.

The panel wrestled with the language, finally deciding to “recommend against routine screening mammography” for women in their 40s.

The intention was to emphasize the word “routine,” but instead people focused on the word “against”. As Dr. Calonge puts it:

No one got beyond that.”

Dr. Otis W. Brawley, chief medical officer of the American Cancer Society, added:

“What the task force was trying to say is that mammography is an imperfect screening tool and there are some harms associated with it, but there are also some benefits associated with it.

“They were trying to say the benefits are not nearly as good as we would all like.”

Media coverage of the resulting controversy leaned heavily towards ignoring or even outright disputing the new guidelines.

For example, the Annals of Internal Medicine ran a review of 109 articles about mammography published over a seven-year period in the six most widely-read U.S. daily newspapers. Their report concluded that the most common theme of these articles about mammography was the issue of screening for women 40-49 years of age:

“Quotes and recommendations in the articles were approximately twice as likely to support as to express reservations about mammography for women aged 40-49 years. Thirty-one percent of the articles studied presented information without citing a source or justification. Recommendations changed little over time, and rarely reflected changes in recommendations of national organizations.”

The researchers’ conclusions?

“Newspapers tend to over-represent support for screening mammography for women aged 40-49 years.

And who was helping to influence this negative media response to the new U.S. Preventative Services Task Force recommendations?

When Senate investigators led by Senator Charles Grassley (R-Iowa) asked opposing groups to reveal any financial backing they receive from the pharmaceutical, medical device and insurance industries, they discovered that the most vociferous critics of the new breast screening guidelines included top officers at organizations like the American College of Radiology and the American Cancer Society, which receive substantial funding from the makers of mammography machines, including Johnson & Johnson, Siemens and Hologic.

NEWS UPDATE:  American Journal of Obstetrics and Gynecology, July 2011*Women overestimate breast cancer risks80% of women in their 40s  overestimated their lifetime risk for the disease, with the average estimate being 37%. The correct lifetime risk for breast cancer is 12%. This is consistent with previous research on breast cancer beliefs.

To put this into perspective, six times more women will die this year from heart disease than from breast cancer.

See also:


* Attitudes of women in their forties toward the 2009 USPSTF mammogram guidelines: a randomized trial on the effects of media exposure; American Journal of Obstetrics & Gynecology, Volume 205, Issue 1 , Pages 30.e1-30.e7, July 2011

5 thoughts on “Clinical practice guidelines vs. routine screening mammograms

  1. This is such a thorny subject. I always thought when I read the USPSTF’s mamm recommendations that they struggled mightily with the language, but still didn’t quite get it right.

    For all women, especially younger women, including those who are under 40, it still comes down to each individual woman having a thorough conversation with her doctor and making the most sensible decisions.

    Then there is the fact that mammography isn’t the best screening device for all breasts or breast tumors. Or even whether digital mammography has been a significant improvement over film mammography. Did you see this article? It raises similar issues about how the rush to replace film mammography units with digital ones took place.

    • Thanks for that link, Kathi. Shocking stuff: “The rise of digital mammography is a tale of intense industry marketing, direct-to-consumer advertising, political lobbying, and strategic campaign donations to politicians … creating the financial incentive for clinics and hospitals to replace film machines with digital ones.”

  2. “….The other 1,899 women will receive no benefit from mammography, though they will field 1,330 call-backs for reassessment and 665 breast biopsies, and eight of them will be diagnosed with cancers whose prognosis will not be altered by detection via mammogram…”

    But women buy into this routine screening policy despite such limited scientific evidence to support its use. Kathi, that information about the wholesale selling of digital mammography is also distressing.

    Consumers need to look at the FACTS, not get sucked into the emotional siren song of high tech tools that are basically not warranted in this age group except for very clear indications.

  3. This is a brave yet ultimately futile argument. On one hand you have science and evidence. On the other hand, you have the Big Money behind financial stakeholders who are spinning this as a bleak picture of necessary screening being WITHHELD from the poor patient. I would compare this dilemma to routine yet unnecessary PSA screening for men’s prostate cancer, a topic you have also covered here.

  4. My breast cancer was identified thanks to routine screening mammography. I do not believe studies that don’t support this type of life-saving screening test.

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