Knowledge gained through clinical trials has been critical to preventing, diagnosing, and treating cancer. However, not all cancer patients benefit equally from these improvements. Nationally, 3% to 5% of adult cancer patients participate in cancer clinical trials (1). Racial/ethnic minorities have represented less than 15% of all adult participants in National Cancer Institute (NCI) treatment trials (2), and a review of Food and Drug Administration (FDA) cancer trials found that adults aged 65 years or older represented barely one-third of clinical trial participants, even though they account for approximately 60% of cancer cases in adults (3). Other adult populations, such as those living in rural areas (4), those who are low income (5), or those without health insurance or third-party reimbursement for clinical trials (5), are also less likely to participate.

Participants in clinical trials should reflect the populations affected by the particular diagnosis (6). Underrepresentation in clinical trials results in disparity in favor of participants who benefit from those trials. From a scientific perspective, diverse representation is necessary to test for differences in outcomes and to ensure the safety of therapies across a range of biological and genetic characteristics (6). From an ethical viewpoint, distributive justice requires that both the benefits and risks associated with clinical trial research be fairly distributed among those who are potentially affected (7). The goals in addressing disparities in clinical trial participation should be not only attaining representative participation among all groups of potential cancer patients but also fair opportunity to be aware of and participate in clinical trials without financial considerations.

The National Institutes of Health (NIH) and FDA mandate the inclusion of women and minorities in clinical trials (8,9). However, researchers have documented barriers to participating in cancer clinical trials. Barriers include lack of awareness (10), lack of being invited or recruited to participate (11), eligibility criteria that may exclude certain groups (12), fear or mistrust of the medical and scientific community, and cultural barriers (eg, language, beliefs, attitudes) (11). In health care systems, physicians may not refer older patients to clinical trials because of concern about toxicity or side effects from the treatment (1) and may exclude patients because of their own prejudices (13). At a policy level, barriers may include the lack of state mandates for insurance coverage for clinical trials and the lack of appropriate enforcement and oversight of existing mandates (6).

Because barriers to and disparities in cancer clinical trial participation exist on multiple levels, addressing these issues requires a comprehensive approach. One such approach is reflected in the comprehensive cancer control (CCC) plan for each state, tribe, territory, or other jurisdiction. The CCC plan approach helps prevent duplication of effort, reduce gaps in interventions, and enhance existing programs by coordinating and integrating community resources within a given state, tribe, territory, or other jurisdiction (14). Through the CCC planning process, various stakeholders, including those representing health departments, national organizations, universities, and local organizations, are brought into a statewide coalition to agree to local priorities and goals and to promote the plan among the stakeholders. These plans provide a basic, initial indicator of how each jurisdiction proposes to address their particular burden of cancer, including addressing disparities in cancer clinical trials. We describe the extent to which existing CCC plans address disparities in clinical trials and, of the plans that do address the issue, which ones come from jurisdictions with third-party reimbursement laws.

Nearly all of the CCC plans we identified addressed clinical trials in general, and most specifically addressed disparities in clinical trials. The themes most often addressed were increasing the number of underrepresented participants in clinical trials and education, awareness, and outreach. In general, themes that emerged were related to barriers that have been documented in the literature. For example, education, awareness, and outreach corresponds to the consistently reported barrier that many patients are unaware of clinical trials (10,12). The lack of available trials has been cited as a barrier, particularly among patients in rural communities (18). These correspondences suggest that CCC planners are aware of existing barriers and are proposing strategies to directly address those barriers.

Although not having health insurance coverage is often a barrier to participating in clinical trials (5,6), even those with insurance coverage sometimes forgo participating in clinical trials because they fear their health insurance will not reimburse them (19). One study found that even after reimbursement laws were in place, clinical trial participation significantly increased for NCI phase II cooperative group trials but not for phase III (20). Conversely, another study found no increase in participation but did report that insurance type was no longer a significant factor in determining whether patients would enroll in cancer trials following mandatory third-party reimbursement legislation (21). These studies highlight the fact that reimbursement laws are not the lone solution to increasing participation in clinical trials. The comprehensive efforts reflected in the 10 themes that emerged in our study are examples of steps that may play a major role in addressing disparities in clinical trial participation.

CCC plans are at different stages of development and implementation. However, some CCC coalitions are already taking concrete steps to address clinical trial disparities. The Cherokee Nation is working with the Oklahoma Society of Oncologists to facilitate access to clinical trials and provide information about available local trials on the CCC Web site (22). The Delaware Cancer Consortium has seen its state's insurance code and regulations amended to cover cancer clinical trial participation (23). Minnesota is using outreach programs and community health workers to educate and increase awareness of clinical trials among racial and ethnic minorities (24). These examples suggest that including disparities in clinical trials as a topic in CCC plans would provide support for CCC coalitions and other local stakeholders to act on it.

Our findings have a few limitations. First is our keyword search strategy. Though we believe our keyword terms are inclusive, we cannot assume that the remaining plans did not cover the themes we identified. Second, there was variability in CCC plan format, specifically with regard to level of specificity. It is likely that the more specific a plan was in describing its clinical trials and disparities in clinical trials goals, objectives, strategies, or actions, the more likely we were to capture it based on our keyword search. Nevertheless, many of the themes that emerged from the information extracted from the CCC plans were consistent with future recommendations from other sources (6,12). Third, the data used in this study were extracted from planning documents made available on the Internet. Therefore, we were only able to capture data that were posted online and not necessarily all existing data.

Increasing the participation of racial/ethnic and other underrepresented groups in clinical trials is a national research objective (25), but to our knowledge, our study is the first to examine the attention given to the issue of disparities in cancer clinical trials in CCC plans. CCC plans are a unique, publicly available resource that can serve as a basic indicator of how the cancer community prioritizes disparities in clinical trials nationally; they have been used in previous studies on tobacco control and human papillomavirus (26,27). Findings from this study serve as a call to action to members of CCC planning coalitions and consortia. As a first step, if they have not identified the specific populations that are not appropriately represented in their local clinical trials, they need to identify them and make it a priority to correct the balance of participation. The next step is to prioritize the incorporation of strategies for overcoming these disparities in their updated or revised CCC plan.

We thank Dr Armin Weinberg and the Eliminating Disparities in Clinical Trial (EDICT) project for their support. We thank Ms Leslie Given for her expertise in CCC planning and valuable input. We thank Ms Karyn Popham and the members of the Behavioral Science Doctoral Seminar for reviewing and providing constructive feedback on this manuscript.

Ms Felder was funded by a predoctoral fellowship, University of Texas School of Public Health Cancer Education and Career Development Program — National Cancer Institute/NIH Grant no. 2R25CA57712. Ms Pena was funded by an unrestricted educational grant from Genentech, Inc.