Consent Forms Spell Out Risks, Benefits of Cancer Trials
Most forms don't mislead or oversell the therapy
THURSDAY, Dec. 26, 2002 (HealthDayNews) -- Many cancer patients who enroll in safety trials of experimental remedies may hold unrealistic expectations about the benefits of the treatment.
But that's not because the consent forms they fill out when signing up are misleading.
That's the conclusion of a new study that found that informed consent documents in phase I cancer studies, which set safe doses for therapies that may or may not have been tested before in people, almost never promise the treatment will directly improve their condition. Most forms don't use the word "cure," and most do a pretty good job of laying out the side effects and potential hazards of the regimen, the study says.
Consent forms "aren't perfect, but the vast majority make it quite clear and quite obvious that this is research," says Dr. Ezekiel Emanuel, an oncologist at the U.S. National Institutes of Health and a co-author of the study. Although most of the studies that were reviewed received National Cancer Institute (NCI) funding, the researchers didn't see a significant difference between consent forms in government-sponsored trials and those paid for by the drug industry.
Emanuel's group found that two-thirds of 272 forms in 1999 mentioned death as a real risk to study participants; only 5 percent raised the possibility of a cure for their illness; and only 1 percent promised some therapeutic benefit from the regimen.
The researchers were "a little chagrined" by the frequent unhedged use of the words "treatment" or "therapy" in consent forms, Emanuel says. These terms may imply proven action against cancer and should always be qualified to reflect the uncertainty of a regimen. The same applies even with drugs that have already been approved for use in other conditions, he adds.
Another weak spot with the forms: Fewer than half of them distinguished between procedures, such as CT scans, that were part of the trial protocol and those that were routine in cancer care.
The situation may have improved some since 1999, when only 16 percent of trials followed a template for consent forms recommended by the National Cancer Institute created during the mid-1990s, Emanuel adds.
The results of the study appear in today's The New England Journal of Medicine.
Previous research has found that only 6 percent of patients in phase I studies respond to the treatment. However, the rate of death from side effects to the therapies is about 0.5 percent.
Since people who participate in phase I studies of experimental cancer regimens often are desperately ill, that's a trade-off they're willing to make. However, some research has found that patients are confused about the purpose of phase I studies, and many believe the trial will offer them therapeutic benefit.
Yet Emanuel says researchers know little about how widespread the confusion truly is among cancer patients. "There's a sort of general law that people believe patients have this misperception, but there's not a lot of great data that shows that," he says.
Dr. Steven Joffe, an oncologist at the Dana-Farber Cancer Institute in Boston who has collaborated with Emanuel, says scientists should start directing more attention to aspects of the clinical-trials process other than the consent form. Research facilities have institutional review boards, or IRBs, to protect human volunteers, and forms "are a thing IRBs can fuss over," says Joffe, who sits on Dana-Farber's panel. "But I'm not sure it's where most of the action is."
Rather, Joffe says, volunteers may be misled by conversations they have with doctors, research nurses and other medical professionals in the clinical trial setting. "We don't know nearly enough about what goes on in those conversations," he says.
Dr. Roger S. Wilson, an anesthesiologist who chairs the institutional review board at Memorial Sloan-Kettering Cancer Center in New York City, calls the latest study "reassuring."
The public's perception of clinical trials is marred by highly visible failures, like the 1999 death of Jesse Gelsinger, who was participating in a gene therapy study, Wilson says. "When something tragic happens folks get the impression that it's basically all bad when it's not."
Like Joffe, Wilson says the doctor-patient dialogue is an area where clarity is vital -- but hard to achieve. "People want to hear exactly what they want to hear. You may say something several times and for some reason or other they just don't digest it."
Roughly 25,000 volunteers participate in NCI-sponsored treatment trials each year, the institute says. Nearly 1.3 million Americans annually are diagnosed with cancer.
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