RAND Study Finds Seniors Not Well Represented In Trials Of New Cancer Treatments, Despite Being The Majority Of Cancer Patients
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March 27, 2003
People age 65 and older are underrepresented in medical studies that test whether promising cancer treatments are safe and effective, raising questions about the applicability of the nation's cancer research to the elderly, according to a RAND Health study released today.
Although seniors represented 61 percent of the people diagnosed with cancer from 1997 through 2000, they made up just 32 percent of the people enrolled in cancer clinical trials nationally during the same period, according to the study published in the April 1 edition of the Journal of Clinical Oncology.
"It is important that cancer clinical trials enroll a representative sample of cancer patients to ensure that the results are applicable to all people who develop cancer," said Dr. Joy H. Lewis, a RAND researcher who headed the study. "As the U.S. population ages a greater proportion of cancer patients will be elderly, and this issue will become even more significant."
The study, the most comprehensive examination of the elderly in cancer clinical trials, suggests the major roadblock to seniors' participation are protocol exclusion criteria, rules that exclude patients from the studies if they have other health problems.
These exclusions include having high blood pressure or other ailments effecting the heart, blood or lungs. Further, more than 80 percent of the trials required participants to be either mobile or capable of living independently. Studies that did not have such exclusions enrolled higher proportions of the elderly.
Lewis said that while some protocol exclusions are clearly justified, more research is needed to determine whether all of the exclusions that keep seniors from enrolling in clinical trials are medically necessary. "When designing a clinical trial, investigators must examine each protocol exclusion to be certain that it is scientifically justified for a particular trial, prior to including it in the protocol."
If exclusions are necessary due to the side effects of promising cancer therapies researchers might alternatively design more trials that focus exclusively on older subjects or that address the treatment of cancer patients with certain other ailments, Lewis said.
"Previous research suggests that investigators may be reluctant to enroll elderly patients in clinical trials. This may be due to preconceived notions about the ability of the elderly to tolerate aggressive therapy," Lewis said. "To ensure that cancer trials develop and evaluate therapies for all patients with cancer, trials need to enroll elderly patients in sufficient numbers."
Patients with cancer are living longer and experiencing better quality of life as a result of new treatments developed through cancer clinical trials. Therefore, adequate representation of many groups in clinical trials has been the focus of ongoing concern. Federal laws now require that cancer trials enroll representative samples of women and members of minority groups, but no similar requirement exists for elderly patients.
Based upon a previous smaller study that highlighted the underrepresentation of seniors in cancer clinical trials, federal officials expanded Medicare in 2001 to include coverage for the elderly enrolled in the trials. However, RAND researchers say their findings suggest that the Medicare reform will not be enough to boost senior participation in cancer studies, since this reform does not involve changes in the design of cancer clinical trials.
RAND researchers conducted their study by examining patient and trial characteristics for nearly 60,000 patients enrolled in 495 federally sponsored clinical trials active from 1997 through 2000. The trials were conducted through 12 regional cooperative groups that coordinate federally sponsored clinical trials at more than 2,000 sites across the nation.
Researchers found that the elderly were even less likely to be enrolled in clinical trials for early stage cancers than in trials for late-stage cancers.
While the elderly represented 41 percent of the participants in clinical trials for late stage-cancers, they made up only 25 percent of the participants in trials for early-stage cancers. People aged 65 and older make up 65 percent of the new cases of late-stage cancers and 57 percent of the new cases of early-stage cancer.
Other authors of the study are Jose Escarce, Meredith Kilgore, Michael Housman and Dana Goldman of RAND Health; and Edward Trimble, Richard Kaplan and Michael Montello of the National Cancer Institute.
RAND Health is the nation's largest independent health policy research organization, with a broad research portfolio that focuses on medical quality, health care costs and delivery of health care, among other topics.