'Unrealistic optimism' a problem in clinical trials of cancer drugs

It is a bedrock of medical ethics that patients may participate in clinical trials only if they give informed consent. This means that patients must get information about the trial, demonstrate that they understand that information, have the mental capacity to make a decision about becoming a research participant and make that decision voluntarily.

But a group of bioethicists, behavioral researchers and physicians are questioning whether “unrealistic optimism” may undermine a patient’s ability to give informed consent.

Having a generally optimistic outlook on life, even when you’re fighting cancer, isn’t a problem for medical research. But unrealistic optimism comes into play when a patient believes he or she is more likely to benefit from a treatment – or less likely to suffer a side effect – than other patients in the same situation. The bias that results from unrealistic optimism could skew a patient’s understanding of the potential risks and benefits of enrolling in a trial.

To find out, the research team sent questionnaires to 72 patients with blood, breast or lung cancers or myelodysplastic syndrome (formerly known as pre-leukemia) who were already enrolled in an early-phase cancer trial. On the whole, the patients realized their cancers were not likely to be cured (either with existing drugs or experimental ones).

But 60% were unrealistically optimistic that the drug being tested would control their cancer, and 63% were unrealistically optimistic that the experimental drug would improve their health in some way. In addition, 39% were unrealistically optimistic that they wouldn’t experience harmful side effects from the drugs in their trials.

“Respondents generally believed that they would fare better than the average patient enrolled in the same trial,” the researchers reported. That’s unrealistic optimism.

More research is needed to determine whether this bias makes it impossible for patients to make a truly informed and voluntary decision to participate in a clinical trial, the researchers said. The solution isn’t likely to be a simple one – just giving patients more information about a trial won’t solve the problem as long as the bias is present, they noted.

The report appears in the January-February issue of IRB: Ethics & Human Research, a publication of the Hastings Center.

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