TUESDAY, Jan. 6, 2004 (HealthDayNews) -- The vast majority of Americans welcome just about every screening test for cancer, a new survey finds.
But a leader of that survey questions whether that enthusiasm is justified, given the imperfect state of screening.
In a national telephone survey of 500 adults, 87 percent said routine cancer screening is almost always a good thing, and 74 percent said finding cancer early saves lives "most or all of the time," says a report in the Jan. 7 issue of the Journal of the American Medical Association.
Yet 38 percent of them said they had experienced at least one false-positive test, a report of cancer when none was present, and many of them said that was "the scariest time of my life," the report says.
It's not just the scare that matters, says Dr. Steven Woloshin, an associate professor of medicine at Dartmouth Medical School and a general internist at the VA Outcomes Group in White River Junction, Vt., where the survey was done. A false-positive report sets off "a cascade of events," which can include biopsies and other tests that can cause physical damage as well as surgery that might not be necessary, he says.
"We should let people know that screening is a double-edged sword," Woloshin says. "They should go into screening only after making an informed decision. Just because a cancer is detected early doesn't mean that it will help you."
Some cancers picked up by screening tests are so slow-growing that they are no danger to an older person, Woloshin says. Prostate cancer is one example he offers.
Autopsies have found small prostate cancers in 30 percent to 50 percent of men who died of other causes at age 75 or older, Woloshin says. Detection and treatment of those cancers would do no particular good, he adds.
Nevertheless, 56 percent of the people surveyed said they would want to be screened for such slow-growing cancers, and two-thirds said they would want to be tested for cancer even if nothing could be done if one were detected.
Enthusiasm for screening can even overwhelm professional advice, the survey finds. It included a question about a highly touted test called full-body computed tomography (CT) scan, which produces a detailed image of the interior of the body.
Such expert bodies as the American College of Radiology and the American Association of Physicists in Medicine discourage full-body CT scans, Woloshin says. But given the choice between having such a scan or an outright gift of $1,000, 73 percent of the people in the survey said they would choose the scan.
That attitude results from "how screening is presented in general, as the right thing to do," Woloshin says. "It is an environment in which everything that detects cancer early is a good thing, with no downside to it."
But Dr. Robert Smith, director of cancer screening for the American Cancer Society, says the enthusiasm for whole-body scan expressed by participants could have been fostered by the way the technology was described in the survey.
"That description was not very realistic," Smith says. "It did not reflect the belief that whole-body CT scans are of uneven quality and uneven performance, with a high number of false positives."
One positive that Smith finds in the survey is that "the public seems to be reasonably well-informed about the possibility of false-positive results."
But he agrees with Woloshin that overenthusiasm is an issue.
"Over the past few years, organizations such as ours have recognized that screening is more complex than has been presented to the public," Smith says. "More and more, we realize that we have to do a better job of informing the public about some of the downsides of screening."