The evidence keeps mounting that mammograms and other tests for cancer—which contribute significantly 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, ages 40 to 59, were divided into two groups; one received annual mammograms for five years and the other did not.
After 25 years, breast-cancer mortality rates in the two groups were virtually identical. Said study also found that more than one in five women diagnosed with cancer because of a mammogram were “overdiagnosed”; meaning that if left untreated, the abnormality detected by the mammogram would never have compromised the woman’s health. These overdiagnosed women thus received treatment–including surgery, radiation and chemotherapy–that they did not need.
A BMJ editorial 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 Canadian 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.”
Excessive medical testing helps explain why Americans pay far more for health care than people in any other nation while receiving relatively poorer care. Over-testing stems in part from 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 potentially unneccessartests and treatments. Physicians also over-prescribe tests and treatments to protect themselves from malpractice suits.
Following are my prescriptions 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 the testing epidemic won’t end without a change in the attitudes of consumers, who too often submit to–and even demand–tests of 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 men and women 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.
John Horgan directs the Center for Science Writings, which is part of the College of Arts & Letters. This column is adapted from one originally published on his ScientificAmerican.com blog, “Cross-check.”