Ethicists Discourage Use of "Unproven" Screening Tests

Ethicists have concluded that whole-body computed tomography (CT) scans and other, what they deem unproven, screening tests have significant risks, and physicians should generally discourage their use when such tests lack data and professional support for their use.

Private companies offer access to these new tests--such as lung scans for smokers, magnetic resonance angiography (MRA) to detect cerebral aneurysm, and whole-body CT--without referrals from a primary care physician. But such testing creates ethical problems, according to the authors of the report, which was published in the March 31, 2009, issue of The American Journal of Bioethics. "Under most circumstances, physicians should discourage individual patient access to screening exams prior to conclusive evidence and professional society endorsement," stated Drs. Ingrid Burger and Nancy Kass, from Johns Hopkins University (Baltimore, MD, USA).

Good evidence supports the use of other screening tests such as colonoscopies, pap smears, and mammograms, according to Drs. Burger and Kass. But problems arise, they reported, when entrepreneurs and doctors encourage access to whole-body CT, which may detect cancer early but has never been proven to save lives. "CT exposes patients to radiation, and high false-positive rates may lead to invasive, risky, and costly follow-up procedures," said Drs. Burger and Kass. "Further, the detection of pseudo disease--that is, cancers that grow so slowly that they never produce symptoms or impact a patient's health---leads to interventions and treatments that provide no medical benefit and may pose significant risk."

Widespread adoption of unproven tests outside clinical trials may also slow research to characterize their risks and benefits, the investigators reported in their article. Some such trials are underway, such as the U.S. National Lung Screening Trial, which has enrolled 50,000 smokers to see whether CT screening for lung cancer can save lives. It will cost approximately US$200 million over eight years. "Randomized controlled trials of screening tests can require thousands of patients, years of follow-up, and high costs to complete," Drs. Burger and Kass conceded.

In light of these obstacles, the researchers contended that physicians may sometimes have compelling reasons to use an unproven screening test for high-risk patients who place a high value on the results. The authors proposed four guidelines to help doctors use new screening tests ethically before there is solid evidence to support their use: (1) Physicians should fully understand the epidemiologic basis for screening tests and the tendency of patients to overestimate the value of screening. (2) Physicians should understand the state of the evidence and professional recommendations surrounding screening tests. (3) Physicians should advocate for research to assess new screening tests and the tendency of patients to overestimate the value of screening. (4) Physicians should understand the state of the evidence and professional recommendations surrounding screening tests. (5) Physicians should advocate for research to evaluate new screening tests. (6) Physicians should not engage in direct-to-consumer advertising of screening tests.

"Consumers may falsely infer that any screening exam advertised by physicians offers more benefits than risks and/or is recommended by physicians as a whole," stated Drs. Burger and Kass. "Given the high likelihood of misleading patients, consumer advertising before screening is endorsed for a population, in our view, is unprofessional."

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