Socioeconomic and clinical factors are key to uncovering disparity in accrual onto therapeutic trials for breast cancer.

To monitor and address disparity in accrual, patient participation in cancer clinical trials is routinely summarized by race/ethnicity. To investigate whether confounding obscures racial/ethnic disparity in participation, all women with breast cancer treated by medical oncologists at City of Hope Comprehensive Cancer Center from 2004 through 2009 were classified by birthplace and self-reported race/ethnicity, and followed for accrual onto therapeutic trials through 2010. Undetectable on univariate analysis, significantly reduced participation by subjects of African, Asian, Eastern European, Latin American, and Middle Eastern ancestries was revealed after accounting for age, socioeconomic factors, tumor and oncologist characteristics, and intrapractice clustering of patients.