LOS ANGELES--The Southwest Oncology Group (SWOG) is generally doing fine at enrolling women and African-Americans into clinical trials but is not doing so well at enrolling elderly patients, SWOG investigators reported at the ASCO annual meeting. SWOG biostatistician Joseph Unger found that the elderly were under-represented in almost every type of cancer clinical trial.
The review was inspired by a heightened concern within SWOG over patient access to clinical trials. Kathy S. Albain, MD, professor of medicine, Loyola University Medical Center, Chicago, is chair of SWOG’s Committee on Women and Special Populations.
In an interview with Oncology News International, she said that "our committee was concerned with the participation of African-Americans and with women in our trials. We also suspected that the elderly might be underserved."
She said that SWOG did this survey "because we wanted to see exactly where we stood with our clinical studies populations vs US census-adjusted SEER cancer rates. What struck us is the dramatic under-representation of the elderly. I did not expect that."
This study became possible because the National Cancer Institute recently made data from the Surveillance, Epidemiology and End Results (SEER) cancer registry more easily accessible. "SEER data became publicly available online, which gave us the capability to generate the most recent population estimates," Mr. Unger said.
SWOG vs SEER
Mr. Unger, of the Fred Hutchinson Cancer Research Center, Seattle, and his colleagues at SWOG analyzed all registrations to SWOG therapeutic trials between 1993 and 1996, and compared the incidence rates of female, African-American, and elderly (65 years or older) patients in SWOG trials with corresponding US population rates derived from 1990 US census and 1992-1994 SEER data.
This analysis revealed that: African-Americans were neither over-represented nor under-represented in SWOG, compared with SEER (10.2% vs 10.1%, respectively).
Women were generally well represented (SWOG 41% vs SEER 43%). Women were under-represented in colorectal, head and neck, and lymphoma studies.
Patients age 65 and over were substantially under-represented in all cancer studies except lymphoma. "The overall rate for SWOG was 25%, compared with 63% for the US cancer population," Mr. Unger said.
In the more common cancers, he said, the differences between the SWOG and US population rates include 9% vs 49% in breast cancer, 41% vs 72% in colorectal cancer, 27% vs 63% in leukemia, and 39% vs 66% in lung cancer.
"These findings suggest that the elderly are currently an under-served population in cancer clinical trials," Mr. Unger said. "In common cancers, new initiatives to better accommodate the elderly should be considered."
Many Factors May Contribute
There are many factors contributing to the underaccrual of elderly patients. Some researchers have suspected that problems with Medicare reimbursement for some aspects of treatment of patients on clinical trials might be one major cause for the low representation of elderly patients, but the National Cancer Institute of Canada, where all such expenses are paid, has noted a similar under-representation of older patients in clinical studies.
"We need prospective studies on both the patient barriers and the physician barriers to participation of older patients in clinical trials," Dr. Albain said.
The National Institute on Aging, in conjunction with the National Cancer Institute, plans in the near future to issue a Request for Proposals (RFP) to study the factors responsible for the low participation of older patients in cancer clinical trials.
