NCPA - National Center for Policy Analysis

"Trial Effect" in Clinical Trials?

February 12, 2004

Does participating in a clinical trial directly improve a cancer patient's treatment outcome? Although clinical trials are conducted to test experimental treatments for the benefit of future patients, some oncologists contend that cancer patients who enroll in trials experience better outcomes than nonparticipants -- a benefit known as a "trial effect."

However, in a study published in Lancet, researchers at the Dana-Farber Cancer Institute found little convincing evidence that such a trial effect exists.

The researchers reviewed 26 published studies that compared the outcomes of cancer patients enrolled in a clinical trial with those not enrolled. According to the researchers:

  • Fourteen studies showed some evidence that trial participants had better outcomes, but only nine of the trials were designed to compare the outcomes of the participants with those non-participants who would have been eligible for the trials.
  • Of these, three studies suggested better outcomes among trial participants than among non-participants; no studies showed that participants had worse outcomes than non-participants.

Although they didn't detect an immediate benefit for study participants, the authors reaffirm the importance of trial participation, and they suggest that their findings should shift the emphasis on recruitment of trial patients.

Source: Stephen Joffe, Jeffrey Peppercorn, Jane Weeks and E. Francis Cook, "Study questions whether cancer patients enrolled in clinical trials have better outcomes than non-participants," Lancet, January 24, 2004.


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