Elderly cancer patients are severely underrepresented in cancer clinical
studies, according to a study published in The New England Journal of
Medicine.* Sixty-three percent of people with cancer in the United States
are age 65 or older, yet this group comprises just 25 percent of patients
enrolled in cancer studies.
The low number of older study patients could affect research results of new
treatments, warn the study authors, leading to uncertainty about whether
new drugs can be tolerated by the elderly at the same dosage levels given to
"The clinical applicability of the results of a treatment trial depends in large
part on whether the sample of patients represents the entire spectrum of
patients" who have the cancer under study, write Laura Hutchins, M.D., and
colleagues from the Southwest Oncology Group (SWOG), which conducts
a large number of cancer clinical trials.
The researchers evaluated enrollment on SWOG studies conducted from
1993 through 1996, which enrolled 16,396 patients. They compared the
proportion of elderly patients in the SWOG studies to the proportion found
in the population of all cancer patients, as reported by the National Cancer
Institute's Surveillance, Epidemiology, and End Results (SEER) Program.
The most striking disparities were found in breast cancer studies, where the
elderly make up 49 percent of patients but only 9 percent of study enrollees;
and in patients over age 70, who comprise 47 percent of all cancer patients
but only 13 percent of study enrollees.
This lack of older patients in studies contrasts sharply to the recruitment of
women and African-Americans. These two groups are represented
proportionately in cancer studies, mainly because researchers have made
concerted efforts to include them in response to federal guidelines
established in the early 1990s.
But no such effort has been made with the elderly, and doctors may be
excluding these patients from studies out-of-hand. A 1994 survey published
in the Journal of Clinical Oncology reported that up to 50 percent of
physicians do not offer clinical trials to patients based on age alone.
Other barriers to elderly participation include misconceptions -- by either
patient or physician -- about the benefits and risks of being involved in a
study; co-existing medical conditions that preclude study enrollment; and
patient fears that doctor's visits and other routine expenses will not be
reimbursed by Medicare. (Until very recently, the healthcare agency did not pay for any
treatment deemed experimental, which includes most cancer clinical trials. In
addition, Medicare generally did not pay for drugs needed to control the
side effects of chemotherapy. President Clinton recently directed the Department of Health
and Human Services, the cabinet-level agency in charge of Medicare, to
immediately begin reimbursing claims for routine patient care costs of clinical
The importance of including the elderly in clinical studies is borne out by a
few targeted investigations, including a SWOG leukemia study reported in
1995. That study found that the elderly with leukemia tend to fare poorly
when they undergo intensive treatment -- treatment that often works with
younger patients. Additional studies show that differences in biology explain
the poor outcomes, and these findings have led to research exploring ways
to increase treatment tolerance in older patients.
Despite these few studies, however, there is a distinct lack of data on the
dosages of chemotherapy that the elderly can tolerate. This void "can be
answered definitively only by prospective enrollment of large numbers of
elderly patients in clinical trials," write the authors.
*The article "Underrepresentation of Patients 65 Years of Age or
Older in Cancer Treatment Trials," appears in The New England Journal
of Medicine, vol. 341, no. 27, pp. 2061-67.