Eligibility Criteria Can Be Deceiving: How Direct and Indirect Exclusion Criteria Affects Recruitment of Under-Served Groups in Breast Cancer Trials

Under-served groups are populations unrepresented or disengaged from medical research or services despite having a disproportionately high healthcare burden. INCLUDE (2017) defined and identified under-served groups such as the elderly, ethnic minorities, and patients in cancer trials with brain metastases, amongst many others. Under-served groups may be directly excluded by strict eligibility criteria, e.g., age limits (typically excluding those over 65 years), pregnant women (typically excluded from vaccine trials), or indirectly, e.g., only providing informed consent materials in written English to populations that include many non-native English speakers, a non-clinical eligibility requirement. In breast cancer research, disparity in clinical trial participation of under-served groups and how this affects results and conclusions is not well researched. The purpose of our study was to assess inclusion and exclusion criteria in published phase III breast cancer clinical trials to establish whether they excluded under-served groups either directly, or indirectly.