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Knowledge and Access to Information on Recruitment of Underrepresented Populations to Cancer Clinical Trials

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Summary (continued)


Research Quality

Since the enactment of the National Institutes of Health (NIH) Revitalization Act in 1993,67 cancer researchers have put increased emphasis on recruitment of underrepresented populations to clinical trials. However, this aspect of the human research enterprise has received attention primarily in the secondary analysis of ongoing clinical trials, rather than as an area of focused scholarship. This reality is clearly reflected in the quality of studies available for this evidence report. One of the positive aspects of the studies available for our review is that they have described a number of barriers and promoters of participation in clinical trials. However, most of the evidence is not based on rigorous studies, and a large proportion of the available studies were not driven by any clear hypotheses. A major weakness of the available evidence is the limited number of studies that compared two or more interventions, especially randomized controlled trials. The quality of the evidence summarized raises some questions about its adequacy to answer our questions regarding barriers and promoters of participation in cancer clinical trials. However, because of the consistency and patterns of occurrence of the identified barriers and promoters, it does provide important insights into future research directions.

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Recommendations and Future Research

Key Questions 1 and 2

  • Much of the available body of evidence was developed as "evidence by convenience" in the context of recruitment difficulties, or in retrospective analyses of recruitment of underrepresented populations across multiple clinical trials. There is a need for well-designed, controlled studies of strategies to improve accrual to cancer prevention and treatment trials. These studies should be hypothesis-driven, and include defined measures of success. They should also meet the usual standards of the NIH peer review process.
  • Investigators should give careful thought to success measures for recruitment of underrepresented populations, and they should avoid setting such measures arbitrarily. Additionally, researchers should evaluate and report recruitment results for underrepresented groups more consistently.
  • More attention should be focused on issues of trial design. If studies are not designed to address problems that are relevant to patients in underserved communities, then even the best recruitment strategies will be ineffective. Similarly, trials that exclude patients with chronic conditions will preferentially exclude the elderly, members of minority groups, and patients with lower socioeconomic status, because they are more likely to have chronic conditions. Hence, recruitment efforts must proceed hand-in-hand with initiatives to design relevant and pragmatic trials.68

Key Questions 3, 4, 5, and 6

  • Because of many underrepresented populations' mistrust of researchers and of research institutions, research efforts to improve participation of underserved populations in cancer clinical trials should be developed within the framework of community-based participatory research, with community involvement through all phases of the research.
  • The need remains for community-based studies to understand barriers to accrual in the community, including attitudes toward clinical trial participation. Whenever possible, such studies should be linked to the implementation of cancer clinical trials, and include actual recruitment as a major outcome. For example, several studies have suggested culturally relevant education as a strategy for improving accrual to cancer clinical trials. There is a need to further investigate the efficacy of culturally relevant education as a strategy to improve accrual to cancer prevention trials and cancer treatment trials.
  • There is an urgent need to understand why participation of the Asian American/Pacific Islander and American Indian/Alaska Native populations in cancer clinical trials is minimal to non-existent. Studies of barriers and promoters of their participation should be linked to opportunities to participate. New research initiatives in this area may require several years before they are fruitful in terms of trial enrollment results.
  • Similarly, there is a continuing need to better understand and improve upon strategies for recruitment of African-American males and Latinos/Hispanics into cancer clinical trials. Ideally, such studies should include documentation of existing barriers within a population as a basis for tailored interventions across the spectrum of barriers and promoters, including awareness, opportunity and decisionmaking.
  • There is a need for further investigation of effective communication strategies, including investigations on the best approach to deliver information about clinical trials, both at the community level and at the point of interaction with the potential participant.
  • In communities lacking established efforts to promote awareness about clinical trials, sufficient time should be allowed for relationships to be built with community members, including community-based providers, before accrual can begin. The period for building such relationships may take several years, but it would vary depending on the community and the existing relationships prior to an intervention.
  • Some interventions (e.g., media-based strategy for Hispanic women) have been shown to be effective in increasing accrual to clinical trials. Such interventions should be replicated, and where appropriate, the results should be disseminated widely.
  • To advance the evidence regarding efficacious strategies for improving enrollment to cancer clinical trials, intervention studies will need to be linked to one or more clinical trials, depending on sample size requirements. The studies should include collection of baseline information regarding prevalent risk factors in the study population. Systematic data collection about barriers and promoters of trial participation should be linked to concrete plans for designing interventions to address such barriers. Moreover, the next generation of studies of barriers and promoters of accrual should be multidisciplinary, including the involvement of community-based participatory researchers, social and behavioral scientists, as well as health economists.
  • There are many barriers to care, and it is unlikely that piecemeal strategies to address these barriers will be effective to promote participation in cancer clinical trials. There is a need for a cost-effective strategy to address barriers to care on multiple levels, and in a manner that can be integrated into the context of the health care system and of the research team. To facilitate the integration of recruitment interventions into health care systems, especially the research team, a study should compare the efficacy of a recruitment intervention specialist to that of usual, opportunistic recruitment practices. The recruitment intervention specialist would be a professional or paraprofessional staff member who is appropriately trained to promote awareness about clinical trials in the community and to help patients overcome barriers to opportunity. Ideally, the recruitment intervention specialist would be indigenous to, or at least have extensive familiarity with, the community targeted by the recruitment effort. Thus, this role would be analogous to that of a patient navigator for clinical trials, and its cost-effectiveness should be investigated.
  • Research to improve enrollment of underrepresented populations in cancer clinical trials must interface with other ongoing initiatives designed to address cancer health disparities through discovery, development, and delivery. Such efforts must overcome the critical disconnect between discovery and development on the one hand, and delivery of cancer care on the other.
  • Substantial resources will need to be dedicated to research efforts to build upon the existing evidence on strategies for improving enrollment of underrepresented populations in cancer clinical trials. Many of the initiatives that contributed to the available evidence were probably not funded. NCI should dedicate adequate funds for well-designed studies of barriers and promoters of accrual to cancer clinical trials.

Further investigation is needed on barriers to recruitment of all of the underrepresented populations, as defined in this report, into cancer-related clinical trials. The specific populations are: African Americans (especially men), Hispanics, American Indians/Alaska Natives, Asian and Pacific Islanders, adolescents, the elderly, and rural populations. Future studies should include the evaluation of culturally tailored strategies to promote awareness about cancer clinical trials among underrepresented populations. Different types of intervention approaches should be considered to promote accrual to cancer therapeutic trials and cancer prevention trials. Research and evaluation of recruitment strategies may yield stronger evidence about ways to improve participation of underrepresented populations in cancer clinical trials. The principal need is for hypothesis-driven research, and ultimately randomized controlled trials, to evaluate the most promising strategies for recruiting underrepresented populations into cancer treatment and prevention trials.

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Availability of Full Report

The full evidence report from which this summary was taken was prepared for the Agency for Healthcare Research and Quality (AHRQ) by the Johns Hopkins University Evidence-based Practice Center, under Contract No. 290-02-0018. Printed copies may be obtained free of charge from the AHRQ Publications Clearinghouse by calling 800-358-9295. Requesters should ask for Evidence Report/Technology Assessment No. 122, Knowledge and Access to Information on Recruitment of Underrepresented Populations to Cancer Clinical Trials.

The Evidence Report is also online on the National Library of Medicine Bookshelf, or can be downloaded as a PDF File (1.1 MB). Plugin Software Help.

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AHRQ Publication Number 05-E019-1
Current as of June 2005


The information on this page is archived and provided for reference purposes only.


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