This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The evidence keeps mounting that mammograms and other tests for cancer—which contribute to the sky-high costs of U.S. health care—do not save lives.
The latest study to reach this conclusion was published this week in BMJ, the British Medical Journal, and involved data from the Canadian National Breast Screening Study. In 1980, 89,835 Canadian women, from 40 to 59 years old, were divided into two groups; one received annual mammograms for five years and the other did not.
After 25 years, the breast-cancer mortality rates of women who received mammograms and those who did not were virtually identical. The study also found that more than one in five women diagnosed with cancer because of a mammogram were "overdiagnosed"; that is, the abnormality detected by the mammogram, if left untreated, would never have compromised the woman's health. These overdiagnosed women thus received treatment--including surgery, radiation and chemotherapy--that they did not need.
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
The researchers conclude that "annual mammography does not result in a reduction in breast cancer specific mortality for women aged 40-59 beyond that of physical examination alone or usual care in the community. The data suggest that the value of mammography screening should be reassessed."
Aneditorial in the BMJ notes that the risks and benefits of mammograms are similar to those of the prostate specific antigen (PSA) test for prostate cancer, which has been shown to have marginal value. (The inventor of the PSA test has called it a "profit-driven public health disaster.") The BMJ editorial urges health-care providers to "reconsider priorities and recommendations for mammography screening and other medical interventions."
The editorial adds, "This is not an easy task, because governments, research funders, scientists, and medical practitioners may have vested interests in continuing activities that are well established."
Indeed. In her typically sharp report on the new mammogram study, veteran New York Times reporter Gina Kolata warns: "The findings will not lead to any immediate change in guidelines for mammography, and many advocates and experts will almost certainly dispute the idea that mammograms are on balance useless, or even harmful."
In a previous column, I note that the "medical-testing epidemic" helps explain why Americans pay far more for health care than people in any other nation while getting relatively poor care. I blame over-testing in the U.S. on the "fee for service" model of American medicine, under which physicians are compensated for the quantity rather than quality of their care. Physicians thus have an economic incentive to prescribe tests and treatments even when they may not be needed. Physicians also over-prescribe tests and treatments to protect themselves from malpractice suits.
Here are several ideas for curbing the testing epidemic: First, the fee-for-service model should be replaced with a different compensation scheme—perhaps one that gives physicians a flat salary with bonuses for improved patient outcomes. Second, malpractice laws should be revised so that doctors don’t prescribe tests simply to avoid lawsuits. Third, we need more reliable studies—carried out by researchers with no conflicts of interest—into the efficacy of tests for cancer and other disorders.
But ultimately, the responsibility for ending the testing epidemic comes down to consumers, who too often submit to—and even demand--tests that have negligible value. Our fear of cancer, in particular, seems to make us irrational. When faced with evidence that PSA tests and mammograms save very few lives, especially considering their risks and costs, many people say, in effect, "I don't care. I don't want to be that one person in a million who dies of cancer because I didn't get tested." Until this attitude changes, the medical-testing epidemic won't end.
Related Posts:
"Why I Won't Get a Colonoscopy": https://blogs.scientificamerican.com/cross-check/2012/03/12/why-i-wont-get-a-colonoscopy/
"Cancer Establishment Admits We’re Getting Overtested and Overtreated": https://blogs.scientificamerican.com/cross-check/2013/08/05/cancer-establishment-admits-were-getting-overtested-and-overtreated/
"ABC Reporter, National Football League Promote Mammograms While Experts Question Benefits": https://blogs.scientificamerican.com/cross-check/2013/11/13/abc-reporter-national-football-league-promote-mammograms-while-experts-question-benefits/
"Celebrities Should Inform Women about Risks as Well as Benefits of Mammograms": https://blogs.scientificamerican.com/cross-check/2013/12/12/celebrities-should-inform-women-about-risks-as-well-as-benefits-of-mammograms/
"How Can We Curb the Medical-Testing Epidemic?": https://blogs.scientificamerican.com/cross-check/2011/11/07/how-can-we-curb-the-medical-testing-epidemic/
Photo courtesy National Institutes of Health and Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Woman_receives_mammogram.jpg.