To your health? Controversy surrounds whole-body scans--a costly screen for silent threats.

You've probably heard a radio ad or driven past a billboard hawking the service. The pitch usually goes something like this: "Sure, you look and feel healthy. But each year, countless people succumb to the silent killers: cancer and heart disease. That's where computed axial tomography scanning can make a difference. A 90-second CT exam at our screening center could reveal lurking disease--before it's too late for your doctor to do something about it. CT screening: It might just save your life."

Such ads are selling one of today's most sophisticated medical technologies. CT scanning looks deep inside the body with low-dose X rays and has been used for decades to pinpoint the problems behind patients' symptoms. As a screening tool, it looks for lumps, bumps, and other irregularities that may signal developing disease.

Radiologists refer to the newly popular CT screening as "whole-body scanning," but the tests typically target just the torso. Some centers will scan the head, though at an additional charge. Most people have the screening done without medical consultation and then take the results to a doctor.

CT-screening centers routinely post testimonials on their Internet sites from customers saved from potentially life-threatening conditions for which they had no symptoms.

That's just one side of the issue.

Critics of this growing medical enterprise are many, including the U.S. Food and Drug Administration, the American College of Radiology, the Health Physics Society, the Conference of Radiation Control Program Directors, and the American Association of Physicists in Medicine. These groups all conclude that CT scanning of apparently healthy individuals isn't ready for prime time.

First, CT scans often turn up suspicious anomalies that may not reflect disease. The extra tests that subsequently result, such as more X rays and tissue biopsies, can not only cost a bundle but also impose their own risks.

Second, a clean scan isn't the same thing as a clean bill of health, since some diseases, including colon cancer, don't ordinarily show up on routine whole-body scans.

Third, when a screening scan finds an abnormality, doctors may feel obligated to treat it, even if doing so isn't likely to increase the person's life expectancy or comfort, notes radiologist Leonard Berlin of Rush North Shore Medical Center in Skokie, Ill. For example, he explains, many small tumors are noninvasive. Because they don't spread, people typically "die with, not of" them, he says.

Finally, scans are expensive. Typically $300 to $1,000, they aren't covered by insurance.

Over the past 5 years, whole-body scanning has become a growth industry, notes Judy Illes of the Stanford (University) Center for Biomedical Ethics. Her group reports in the August Radiology that most centers offering the scans are freestanding, for-profit screening centers not associated with hospitals. They're popping up in shopping malls, along interstates, and even in mobile vans, but only in communities whose residents are wealthy and well educated.

"They thrive on what I call the 'worried well,'" Berlin observes.

"This whole thrust toward whole-body scanning is clearly profit driven on the part of the providers," says William J. Casarella, who heads the radiology department at the Emory University School of Medicine in Atlanta. The for-profit scanning centers charge full price for their services and require payment up front. In contrast, Casarella's university center "winds up with only about 40 percent [of the billed amount] from insurance companies."

Despite all the criticism of whole-body scanning centers, screening with CT undoubtedly has saved some lives. A few preliminary studies have suggested that CT screening might prove a boon for scouting out particular diseases in at-risk patients. The best known is the Early Cancer Action Project, which in 1999 showed that CT screening of long-time smokers found four times as many lung cancers as conventional chest X rays did.

A National Cancer Institute study plans to give lung scans to 50,000 current and former smokers to evaluate whether such screening can detect cancer in time to save lives. Lung scans are an element of whole-body screening exams.

Most radiologists would prefer to have had the results of such trials before whole-body scanning ads began flooding the airways. "But scanning centers are out there now, so we have to do more than just wring our hands," says Illes. She argues that "we have to put in place a set of operating guidelines today for these centers," requiring that, at a minimum, they better inform consumers of what they should and shouldn't expect of the costly tests.

TAKE HEART Physicians have been prescribing CT scans, formerly known as CAT scans, since the mid-1970s. "Many order whole-body [scans], not calling them that," observes radiologist Michael Brant-Zawadzki of Hoag Memorial Hospital in Newport Beach, Calif. Last year alone, he notes, U.S. hospitals and other centers performed some 35 million CT scans.

More and more of those scans are for screening rather than just homing in on the source of symptoms, says Brant-Zawadzki. What's relatively new is who's ordering up many of the full-torso scans: symptomfree consumers, usually without consulting their doctors. Fueling this trend, he says, are baby boomers' preoccupation with wellness, relatively high standard of living, comfort with new technology, and dissatisfaction with insurance that limits access to some doctors and procedures.

Furthermore, Brant-Zawadzki maintains, some physicians approve of the screening as "an ounce of prevention," although whole-body scanning hasn't been endorsed by much research.

Though Brant-Zawadzki is "not a big proponent of whole-body scanning," he says he does perform some CT screening at patients' requests. Why? At least for people at elevated risk of heart disease (SN: 9/13/03, p. 174) and lung cancer, CT scans can find hidden disease.

"For 180,000 people a year, the first sign of coronary artery disease is death," he says. CT screening highlights calcification of coronary arteries, providing direct evidence of disease. Since one in three men has such artery disease by age 40, "why not allow men over 40 direct access to this screening test?" Brant-Zawadzki asks.

"I had my coronaries tested," he told Science News, "and now I'm on [a cholesterol-lowering drug] and aspirin because I had calcification"

George T. Kondos, director of clinical cardiology at the University of Illinois at Chicago College of Medicine also supports CT heart scans for apparently healthy people.

His team used CT scans to determine the calcification of coronary arteries in 8,855 initially asymptomatic adults. Then they divided the volunteers into four groups according to their calcification scores. Over the next 3.5 years, men in the highest-calcification group were 2.3 times as likely to die of heart problems or have a heart attack, and 10 times as likely to need bypass surgery or an unclogging of arteries, as were men in the three lower-calcification groups. Women with the highest calcification were 3.8 times as likely to need surgery to clear or shunt blood around a coronary artery as were those with the lowest calcification, the researchers reported in the May 27 Circulation.

Kondos says, however, that CT screening isn't warranted in people clearly at either low or high risk of heart disease. Low-risk people, such as nonobese nonsmokers without a worrisome family history, don't need the test. High-risk people should take preventive measures without this costly procedure. CT'S value will come in discriminating the nature of disease in people at intermediate risk, which Kondos says include all men over 45 and those women over 50 with at least one additional risk factor, such as high cholesterol.

Cardiologist Matthew Budoff of Harbor-UCLA Medical Center in Torrance, Calif., says that CT screening for heart disease "can be easily justified in most people over a certain age." He calls such testing "the most medically valid" aspect of whole-body CT screening.

A FLUKE? In contrast to heart tissue, most abdominal organs reveal little detail in CT scans unless a radiologist injects a person with an iodine-based contrast dye before the scan. That's not done in most whole-body scans of symptomfree people, Berlin notes, because it increases costs and some people prove allergic to the dye.

Yet University of Miami urologist Raymond J. Leveillee says that he and his colleagues have caught several kidney tumors in patients who had received whole-body scans without contrast dye.

Last year, for example, a physician referred a patient to Leveillee's department for removal of a kidney after a suspicious spot showed up on a whole-body scan at a for-profit center. Shortly thereafter, a second kidney-cancer case was flagged the same way. "By the time the third and fourth arrived," Leveillee recalls, "we thought, 'This is weird.' We were seeing a lot of big tumors in people with zero symptoms." Indeed, at least one person had gone in for scanning only because he had received the screening as a birthday present.

Leveillee and his colleagues then reviewed the cases of some 30 kidney cancer patients they'd seen over the previous 6 months and found that for seven of them, the first hint of trouble came when doctors noticed a suspicious spot on a whole-body CT scan. The Miami physicians reported their findings at the May meeting in Chicago of the American Urological Association.

"A year ago, I probably would have said [whole-body CT screening] was a waste of money," Leveillee says. But here, "in at least a half-dozen cases, it has probably saved people's lives." Indeed, he says, "when I get to be 45 or 50, I'll probably jump on the table for my own [scan]."

SIZABLE COSTS Despite the success stories, most anomalies that whole-body scanning turns up aren't clear signs of disease. Casarella knows firsthand how nontrivial the resolution of such a finding can be.

A few years ago, a dye-enhanced CT scan targeted at his own colon picked up nodules in the background. The procedure found lesions on a lung and two abdominal organs, suggesting a cancer that was spreading. These spots, Casarella notes, are exactly the type that shows up in whole-body CT screening.

The nodules turned out to be scars from an old infection. But Casarella's doctors didn't find that out until they did a biopsy. It required surgery in which they needed to collapse his lung. He then faced a substantial hospital stay. Total cost: roughly $40,000, paid for by Casarella's insurance.

This highlights one public health implication of the nation's growing infatuation with whole-body scanning, says Kim Howard, a Longview, Texas-based radiologist who reviewed CT screening as an advisor to his state's bureau of radiation control.

Some people argue that since consumers pay for whole-body scanning out of their own pockets, they're the only ones who stand to lose anything financially, says Howard. "In fact." he says, "it becomes a public cost the minute a nodule shows up." Then, public or private health insurance steps in to cover any additional procedures needed to resolve or treat the abnormality.

Such costs could bankrupt the U.S. health-care system, he says, pointing to a Mayo Clinic study in the March Radiology. Stephen J. Swensen and his colleagues performed annual CT scans of the lungs in 1,500 current or former smokers. Each was at least 50 years old and showed no symptom of cancer. After 2 years, the screening turned up 41 true cancers--and another 2,800 questionable nodules. Some 70 percent of all the volunteers in the study had at least one questionable nodule.

On the basis of subsequent biopsies and surgery on some people in the study, follow-up scans, and data from earlier work, Swensen's group concluded that nearly 99 percent of the questionable nodules that they detected were benign. Extrapolating this rate to the nation's 90 million current and former smokers suggests they harbor some 150 million similarly benign nodules that would masquerade, on scans, as cancer.

"That is the 'fly in the ointment' that concerns all of us involved in screening," Swensen observed in an October 2002 commentary in the American Journal of Roentgenology. "One important feature of a useful screening test is a low false-positive rate," he noted. "CT apparently will not meet this criterion"

Swensen's team picked up new nodules in the study volunteers in each subsequent year's scans. That, Howard notes, brings up the question of how frequently any screening would need to be repeated to prove useful. Most cancers tend to appear sporadically after age 50. So, he argues, "if you don't do periodic screening, you're going to miss the vast majority of cancers." However, he says, frequent CT screening risks exposing healthy people to potentially carcinogenic amounts of radiation.

In general, a whole-body CT scan exposes the body to a radiation dose that's about 30 times that of a standard chest X ray--by itself, not a big deal, most radiologists say. However, once a suspected cancer shows up, doctors will usually request repeat, higher-dose CT scans--in some cases, up to five focused scans over the next 2 years--notes radiologist Philip C. Goodman of Duke University in Durham, N.C. At the Radiological Society of North America meeting last year, he reported the cumulative radiation dose from such a follow-up is "going to be hundreds of times that of a chest X ray."

Risks and cost of follow-up procedures are among the complications of whole-body CT scanning that many people won't recognize when they sign up for it, says Berlin.

"That's why we need guidelines for these centers," Illes contends. She'd like to see doctors, bioethicists, and others evaluate current information on CT screening and then make recommendations for a code of conduct. That code, she says, might insist that whole-body scanners disclose in their advertising which organs these scans don't image well. Berlin would like them to also provide typical false-negative and false-positive rates, the costliness and potential dangers of follow-up testing, and how frequently people need to be scanned to catch diseases as they develop.

Indeed, Casarella says, "I don't have any problem with patients referring themselves for CT screening. We just need to be careful that we tell them what the benefits and risks are."

No one, he adds, should have to pay for "a false sense of security or false sense of anxiety."