Inequities in enrollment across clinical trial phases and the need for a Spanish perspective

Abstract

Early phase clinical trials (EPCT) are essential for evaluating new cancer treatments. However, disparities in patient enrollment persist, especially affecting older adults, minority groups, and individuals of lower socioeconomic status. In Spain, despite its leading role in European clinical research, systematic analysis of inequalities in EPCT participation remains underexplored. This narrative review identifies and discusses key barriers affecting patient access to EPCTs in Spain, including strict eligibility criteria, socioeconomic and geographic barriers, differences in hospital resources, and biases among clinicians when selecting patients. Recommendations provided include revising eligibility criteria, improving training for healthcare professionals, enhancing referral networks, providing targeted education for patients, and addressing socioeconomic and geographic constraints. Addressing these barriers is essential to ensure equitable EPCT participation in Spain and to improve overall cancer outcomes.

Keywords: Cancer; Clinical trials; Disparity; Early phase clinical trial; Inequalities; Recruitment; Socioeconomic status.