Diversity among clinical research subjects is essential for ensuring that trial results are generalizable to the full population of patients.1 In addition, trial participation may provide direct benefit to patients, who as subjects may receive more comprehensive care and access to experimental treatments not otherwise available. For these reasons, cancer centers routinely monitor disparity in accrual onto therapeutic trials by race/ethnicity and gender. This monitoring serves to inform institutional efforts to eliminate disparity in clinical trial participation.2
Studies of cooperative group trials3–5 have concluded that African American,3–5 Asian,4,5 and Hispanic3–5 patients are accrued at lower rates than non-Hispanic white patients. However, systematic reviews6,7 have concluded that the quality of studies on barriers to participation in cancer clinical trials is poor, with many threats to internal and external validity (eg, selection bias, poor survey design, hypothetical vs documented participation).7 Uncontrolled confounding by socioeconomic factors threatens the validity of reported associations with race/ethnicity.3–6 According to a national study of patients with breast cancer aged 65 years or older,8 after age and county economic attributes are accounted for, African and Asian patients are no less likely and Hispanic patients are nearly 3 times more likely to participate in trials than Caucasian patients.
When evaluating disparities in clinical trial accrual, potential confounding factors are not limited to socioeconomic characteristics of the patient or her community. Clinical factors, such as younger age,9,10 more advanced stage of disease,9,10 newly diagnosed status,10 good performance status,10 and having an oncologist who is a principal investigator of breast cancer trials,11 promote the likelihood that a patient with breast cancer will be offered a trial. The treatment setting also plays a role: centers with approved cancer programs (ie, comprehensive cancer centers) tend to promote accrual onto clinical trials more than other centers.5
To understand the extent to which socioeconomic and clinical factors may obscure disparity in accrual, the authors identified all women with breast cancer treated by medical oncologists at City of Hope Comprehensive Cancer Center in recent years; classified them per birthplace and self-reported race/ethnicity as primarily of African, Asian, Latin American, Eastern European,
Characteristics of Patients With Breast Cancer at First Visit, by Trial Accrual Status
Dr. Hurria has disclosed that she is a PI on investigator-initiated research funded by GlaxoSmithKline and Celgene Corporation; she is a consultant and advisory board member for GTx, Inc.; and is a consultant for Seattle Genetics, Inc. and Boehringer Ingelheim GmbH. The remaining authors have disclosed that they have no financial interests, arrangements, affiliations, or commercial interests with the manufacturers of any products discussed in this article or their competitors. This research received support from the National Cancer Institute of the National Institutes of Health under grant number P30CA033572. The content of this report is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
The authors wish to thank Yan Shen, MS, Leanne Goldstein, DrPH, and Sharla Moore, MPH, for assistance with data collection, and Linda Brown, MLS, for helpful discussion about health literacy.
Inclusion of women and minorities as participants in research involving human subjects - policy implementation page. National Institutes of Health Web site. Available at: http://grants.nih.gov/grants/funding/women_min/women_min.htm. Accessed November 30 2013.
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