The findings, published online today in Cancer, are particularly worrisome as the cancer burden increases among growing diverse populations, which already constitute the majority in California, Texas, Hawaii, New Mexico, Washington, D.C. and Puerto Rico, and the associated disparities in cancer incidence and mortality become even more prominent. Clinical trials are considered essential for the discovery and development of better drugs and treatment methodologies to treat cancer, and participation in trials has been shown to lower cancer mortality in patients with some types of tumors.
Led by Professor Moon Chen, researchers at the UC Davis Comprehensive Cancer Center examined online citations from medical publications to determine how frequently data based on minorities in clinical trials were reported and analyzed.
Chen explained that just as efforts were made decades ago to increase participation of women in clinical research, emphasis on minority-focused research and clinical trials recruitment is needed to increase the participation of all racial/ethnic populations in cancer clinical studies.
“The proportion of minorities in clinical research remains very low and is not representative of the U.S. population with cancer,” said Chen, the cancer center’s associate director for cancer control. “What is needed is deliberate effort. Minorities are not hard to reach. They are hardly reached.”
To assess minority inclusion in clinical trials, Chen and his colleagues searched ClinicalTrials.gov, the official NIH website for all registered clinical trials, and looked for trials sponsored by the National Cancer Institute available during the month of January 2013. They searched using terms for different minority groups then counted the number of clinical trials with a primary focus on a particular ethnic or minority population. They found that only about 150 trials, out of about 10,000, or less than 2 percent, met the criteria.
They also reviewed abstracts and articles accessed from January through March 2013 on PubMed, a comprehensive online database of published research findings, to find articles that specifically examined minority accrual in clinical trials. Of the 42 citations found, only five included reports explicitly discussing participation levels by race and ethnicity. Those reports revealed an “encouraging but less than optimal” increase in specification of race or ethnicity in published results of clinical trials.
Overall, the authors report that participation of adult minorities is not proportional to their representation in the U.S. population. Clinical trial participation is low for all adult groups (3 to 5 percent), and the percentage of minorities who participate in clinical trials is not representative of the U.S. population affected by cancer. For example, blacks experience the highest incidence of cancer (593.7 cases per 100,000 people) but, along with Hispanics, have the lowest rates of cancer clinical trials participation at 1.3 percent.
By contrast, the researchers note that a full 60 percent of all patients under age 15 are enrolled in clinical trials, and minority representation among children is excellent, either equal to or greater than their proportion of the population.
“The record of participation by racial/ethnic populations in pediatric clinical trials suggests that a comparable record is potentially achievable in clinical trials for adults,” the authors stated in the study.
The value of minority participation in cancer clinical trials has been well documented, said Karen Kelly, a co-author and associate director for clinical research at the UC Davis Comprehensive Cancer Center. She cites as an example the observation that a certain genetic mutation that predicts responsiveness to an oral therapy known as EGFR-TKI is more frequently found in lung tumors from Asian patients than in their American counterparts. The finding allowed for rapid completion of a large randomized study conducted predominately in Asian countries that proved the superiority of EGFR-TKI over traditional chemotherapy and changed how lung cancer is treated worldwide. Interestingly, side effects from EGFR-TKIs are more frequent in Asian patients than in Caucasians. The data suggests that ethnic and geographic differences play a significant role in cancer pathogenesis and drug metabolism.
“In lung cancer, it opened our eyes,” said Kelly. “Clinical trials in diverse populations can help us understand the biology of disease, and why a drug may produce a higher response rate and higher toxicity in one group than in another. Moreover by targeting the population most likely to benefit from a novel treatment we can accrue patients more quickly to clinical trials that will lead to faster results.”
The authors acknowledge that barriers to clinical trials participation still exist among minorities, including mistrust, costs, transportation and cultural differences. But they also cite research demonstrating that there is no correlation between clinical trials awareness and willingness to participate.
One way UC Davis Comprehensive Cancer Center is addressing the problem is with a new program that provides every Asian-American cancer patient with culturally sensitive clinical trials educational materials and specially trained patient navigators for trial enrollees. AACES, or Asian-American Cancer Education Study, was developed by the Asian American Network for Cancer Awareness, Research and Training (AANCART), which is housed at the cancer center.
“The solution is not changing the attitudes of minorities but rather in ensuring access to health research,” the authors argued. Clinical trials should be designed to include and focus on specific populations, and scientific journals should insist on appropriate representation and analyses of NIH-funded research by race and ethnicity, they concluded.
“Whatever happens in the laboratory or in the clinic needs to be applied to solving real-world problems, and those relate to the disproportionate effects of cancer and other diseases on racial and ethnic minorities,” said Chen.
This research was supported by the National Institute on Minority Health and Health Disparities, grant No. 1U24 MD006970, and the National Cancer Institute, grant No. U54CA153499.
UC Davis Comprehensive Cancer Center is the only National Cancer Institute-designated center serving the Central Valley and inland Northern California, a region of more than 6 million people. Its specialists provide compassionate, comprehensive care for more than 10,000 adults and children every year, and access to more than 125 clinical trials at any given time. Its innovative research program engages more than 280 scientists at UC Davis, Lawrence Livermore National Laboratory and Jackson Laboratory (JAX West), whose scientific partnerships advance discovery of new tools to diagnose and treat cancer. Through the Cancer Care Network, UC Davis collaborates with hospitals and clinical centers throughout the Central Valley and Northern California to offer the latest cancer-care services to their communities. UC Davis’ community-based outreach and education programs address disparities in cancer outcomes across diverse populations. For more information, visit http://cancer.ucdavis.edu.