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Here are the odds. To save the life of one woman in her 40s, 1,904 would have to undergo annual screening. Beyond inconvenience and overexposure to radiation, this excess mammography would lead to false positives; psychological stress, including depression; and unnecessary surgery. In addition, much of the abnormal cell growth detected in women in their 40s could have been detected in their 50s with no adverse effects from the delay.
Not surprisingly, many women railed against the new USPSTF guidelines. Understanding a statistic is one thing. Accepting even the slim chance that you could die of a treatable disease to spare others unnecessary harm is less clear-cut. No woman cares about collateral damage when her life could be at stake.
Colonoscopy, the examination of the colon from within to look for cancer and precancerous polyps, is an accepted standard of care. Doctors often advise average-risk patients to get a colonoscopy at age 50 and, if nothing suspicious is found, every 10 years after that. (See Dr. Oz, page 50.) Yet this advice is given despite the fact that no long-term randomized trial the industry standard for amassing bulletproof data has shown colonoscopy, a highly invasive procedure, to be more effective at saving lives than a simple test looking for blood in fecal material or a sigmoidoscopy, a procedure in which just a portion of the colon is examined. One advantage of colonoscopy is that doctors can screen for cancer and intervene if they suspect it, removing suspicious lesions while the patient is still on the examination table. (The USPSTF says colonoscopy, sigmoidoscopy and the fecal-blood test can all be effective.)
Other kinds of screening, like for prostate cancer, are even more contentious. Multiple scientific trials have proved that the ubiquitous prostate-specific antigen (PSA) test saves very few lives, if any. PSA tests are notoriously unreliable, detecting potential cancers where there are none and returning normal results in some men who have malignancies. The doctor who discovered the existence of PSA, a protein that, when elevated, is sometimes an indication of cancer, has disavowed the test, calling it a "profit-driven public-health disaster."
Of men who undergo routine PSA testing, a staggering 17% are eventually diagnosed with cancer, and most of these are treated with radiation or surgery. At least half experience complications such as erectile dysfunction or incontinence. Much of this is needless suffering, since the vast majority of men diagnosed with prostate cancer will not die of it, even if it is left untreated. In fact, for every 1,000 men ages 55 to 70 who undergo annual PSA tests for 10 years, only one life might be saved, according to Welch, who has conducted extensive study on the topic. Meanwhile, an estimated 150 to 200 will have an unneeded biopsy, and 30 to 100 will undergo radiation treatment or have their prostate removed unnecessarily. Despite its ineffectiveness, some 30 million American men have a PSA test every year, partly because it's the best we have for now and prostate cancer remains a deadly disease, killing about 32,000 men annually in the U.S.
Impotence and urinary dysfunction are awful, but the history of poorly designed cancer screening includes tests with much more dire consequences. In the 1960s, many doctors advised American smokers to get chest X-rays to check for lung cancer, the No. 1 cancer killer in the U.S. In the 1970s, the ACS followed suit, and millions heeded the advice. Yet a decade later, studies showed that Americans who were screened for lung cancer via chest X-ray actually had a slightly higher mortality rate than those who were not screened. The excess deaths were due in part to the risky surgery that patients underwent when something was found.
As recently as the 1980s and '90s, doctors in Japan and Quebec screened babies for neuroblastoma, a cancer of the nerve tissue that's the most common type of cancer in infants. The screening revealed alarmingly high cancer rates. "People thought there was a neuroblastoma epidemic," says the ACS's Brawley. "Kids started getting biopsied and then getting surgery, which means basically being filleted open for an 18-month-old." The result was the same as with lung-cancer screening. Mortality rates were slightly higher among the screened population because of deaths caused by surgery. The screening was discontinued. Doctors, it turned out, couldn't distinguish between fatal neuroblastoma and the far more common kind that simply vanishes over time.
Cascades and Incidentalomas
Dr. Jim Mold did not want a PSA test. A family doctor trained in geriatrics, Mold had published journal articles about the hazards of screening and of medical intervention for men with prostate cancer. So it made sense that even though he was 58, solidly in the risk group for prostate cancer and in his doctor's office for a series of unrelated blood tests, he had chosen to forgo a PSA test. He got one anyway. It had inadvertently been added to his order. He noticed at the last minute but didn't protest.