Enrollment patterns and site-level predictors of Black participant recruitment to a multisite randomized clinical trial (RCT) of endocrine therapy adherence support.

Abstract

68 Background: Accrual of racial and ethnic minority patients (pts) to clinical trials has been an ongoing challenge in research. Barriers exist at many levels of engagement including trial availability, screening biases, strict enrollment criteria, and structural racism. Lack of trial diversity has led to less generalizable medical evidence, suboptimal data for toxicity and efficacy of cancer treatments, poorer outcomes and continued mistrust by communities of color in research processes that exclude or marginalize them. Site factors and study design strategies associated with successful recruitment of diverse study populations are understudied. Methods: Alliance A191901 is an RCT testing combinations of text and telephone support to promote endocrine therapy adherence among breast cancer survivors. It oversamples Black participants and those < 50 years at thresholds of 30% each. Administrative enrollment data was used to track and describe monthly accrual trajectory by race among the initial 50% of participants (n = 590) and to examine associations between % Black participants accrued and accruing site characteristics, including site type, geographic region, % Black population in the site’s zip code and volume of pts by race accrued to recent (2018-2019) Alliance trials, using χ2 tests. We also examined patterns of Black participant accrual before and after closure of the A191901 study to non-Black participants. Results: At 50% accrual, 124 sites had enrolled at least 1 participant. Among 590 participants, 9.7% were Black and 22.5% were < 50 years. Neither site type nor volume was associated with % Black participants recruited. Sites in the South recruited higher proportions of Blacks (19.0% vs 5.6% for Midwest, the lowest region, p < 0.001). Neighborhood racial composition was positively associated with accrual of Black participants (17.2% at sites from highest Black composition vs. 2.3% in lowest, p < 0.001). Recruitment trajectories of Black participants consistently lagged those of non-Black participants in the first half of the study; however, Black participants recruited per month numerically increased after the study reached target accrual of non-Blacks and closed to non-Black participants. Conclusions: Sites in neighborhoods and geographic regions with larger Black populations recruited higher proportions of Black participants, but site type and volume were not associated with recruitment of Black participants. Closure of non-Black study strata based on predetermined accrual targets may positively impact recruitment trajectories of Black participants, but further study is needed. Site selection based on neighborhood composition and geography may be an appropriate tool for increasing trial diversity. Support: UG1CA189823. Clinical trial information: NCT04379570.

From Race to Racism and Disparities to Equity

“…Other innovations in the structure of the clinical trials system will be necessary to truly foster diversity and representativeness, including decentralization of research to locations near patients of color 100 . In a recent analysis of accrual patterns by race for a large breast cancer cooperative group trial that oversamples Black women, we found that the most important site-level predictor of high accrual of Black patients was the proportion of Black residents in the zip code where the trial site was located 101 . Other key strategies, as outlined in a recent policy statement from the American Society of Clinical Oncology and Association of Community Cancer Centers, include education of the research workforce on equity, diversity, and inclusion issues and diversifying the workforce itself to reflect the communities in which cancer research is performed 102 .…”

“…100 In a recent analysis of accrual patterns by race for a large breast cancer cooperative group trial that oversamples Black women, we found that the most important site-level predictor of high accrual of Black patients was the proportion of Black residents in the zip code where the trial site was located. 101 Other key strategies, as outlined in a recent policy statement from the American Society of Clinical Oncology and Association of Community Cancer Centers, include education of the research workforce on equity, diversity, and inclusion issues and diversifying the workforce itself to reflect the communities in which cancer research is performed. 102 A large community of breast cancer advocates and survivors exists, including many people of color, which can be leveraged to better represent all patients with breast cancer in clinical trials, if researchers and regulators make this a priority.…”