BOSTON -- 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 non-participants - a benefit known as a "trial effect."
In a study to be published in the Jan. 24 issue of the journal Lancet, researchers at Dana-Farber Cancer Institute and their colleagues report that a review of more than two dozen published cancer studies comparing outcomes among trial and non-trial patients found little convincing evidence that such a trial effect exists. They caution that more research is needed to determine whether there is a predictable benefit from trial participation.
"Clinical trials are critical to the advancement of cancer care, but it is important that people who enroll in a study understand that their participation is intended primarily to benefit future patients," says Jeffrey M. Peppercorn, MD, MPH, a clinical fellow at Dana-Farber and the paper's first author.
The researchers reviewed 26 published studies that compared the outcomes of cancer patients enrolled in a clinical trial with those not enrolled. 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.
"We found a few instances in which cancer trial participants may have had better outcomes than non-participants, but the limitations of the data we reviewed made it difficult to establish a definitive link between trial participation and improved outcome," explains senior author Steven Joffe, MD, MPH, who is an instructor in pediatrics at Dana-Farber and at Children's Hospital Boston and Harvard Medical School.
Although they didn't detect an immediate benefit for study participants, Peppercorn and Joffe reaffirm the importance of trial participation, and they suggest that their findings should shift the emphasis on recruitment of trial patients. "We strongly encourage cancer patients to consider enrolling in clinical trials because their involvement can help improve cancer treatments over time," says Peppercorn. "Many patients find it rewarding to know that they are contributing to the larger fight against cancer."
The study was funded in part by the National Cancer Institute.
The paper's other authors are Jane C. Weeks, MD, of Dana-Farber, and E. Francis Cook, ScD, of Brigham and Women's Hospital and Harvard School of Public Health.
Dana-Farber Cancer Institute is a principal teaching affiliate of the Harvard Medical School and is among the leading cancer research and care centers in the United States. It is a founding member of the Dana-Farber/Harvard Cancer Center (DF/HCC), designated a comprehensive cancer center by the National Cancer Institute.
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