Factors associated with age disparities among cancer clinical trial participants

Abstract

Importance: Seminal investigation 2 decades ago alerted the oncology community to age disparities in participation in cooperative group trials; less is known about whether these disparities persist in industry-funded research. Objective: To characterize the age disparities among trial enrollees on randomized clinical trials (RCTs) of common cancers in clinical oncology and identify factors associated with wider age imbalances. Data Sources: Phase 3 clinical oncology RCTs were identified through ClinicalTrials.gov. Study Selection: Multiarm RCTs assessing a therapeutic intervention for patients with breast, prostate, colorectal, or lung cancer (the 4 most common cancer disease sites) were included. Data Extraction and Synthesis: Trial data were extracted from ClinicalTrials.gov. Trial screening and parameter identification were independently performed by 2 individuals. Data were analyzed in 2018. Main Outcomes and Measures: The difference in median age (DMA) between the trial participant median age and the population-based disease-site-specific median age was determined for each trial. Results: Three hundred two trials met inclusion criteria. The trials collectively enrolled 262354 participants; 249 trials (82.5%) were industry-funded. For all trials, the trial median age of trial participants was a mean of 6.49 years younger than the population median age (95% CI,-7.17 to-5.81 years; P