Exclusion of Older Adults from Cancer Clinical Trials: Review of the Literature and Future Recommendations

In this review, we present the context of older adult (OA) cancer patients within the broader cancer population, including cancer burdens and trial representation. We first describe the proportion of older adults in clinical trials, with studies showing strong evidence that the proportion of OA in cancer trials is much less than the proportion of OA in the overall cancer population. We highlight the lack of generalizability that can lead to challenges in treatment decisions for OA as well as concerns regarding health inequity. We then discuss barriers to OA enrollment related to trial structure and design, physician perspective, and patient and/or caregiver perspective. We expand on this further by outlining these barriers throughout the process of trial design, patient enrollment/trial implementation, and data analysis in post-market settings. We summarize guidelines from national societies, regulatory agencies, and other institutional bodies, then present a compilation of on-the-ground actionable recommendations to address the challenges of clinical trial design, focusing on geriatric assessments and OA-specific trials. We conclude by providing an outline for future directions, noting specifically the potential impact that radiotherapy and radiation oncology may have on clinical trials related to OA patients.