Nonmetropolitan residence and other factors affecting clinical trial enrollment for adolescents and young adults with cancer in a US population-based study

Background Cancer survival rates in adolescents and young adults (AYAs) have shown slow improvements in comparison with other age groups, and this may be due to lower participation in clinical trials. Little evidence has been provided regarding how nonmetropolitan residence may influence clinical trial enrollment for AYAs with cancer. This study sought to determine whether AYAs from nonmetropolitan areas have lower rates of clinical trial enrollment than their urban counterparts and to examine factors associated with enrollment variation. Methods Data from the National Cancer Institute's 2006 and 2013 Surveillance, Epidemiology, and End Results Patterns of Care AYA cohorts were analyzed. Patients with acute lymphoblastic leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma, and sarcoma were included (n = 3155). Urban influence codes were used to measure the rurality of the county of residence at diagnosis, which was categorized as large metropolitan, small metropolitan, or nonmetropolitan. Logistic regression compared trial participants and nonparticipants while adjusting for patient and provider factors. Results Compared with AYAs from large metropolitan counties, AYAs from small metropolitan (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.57-2.64) or nonmetropolitan counties (OR, 1.86; 95% CI, 1.23-2.81) experienced greater trial enrollment. AYAs treated at a hospital with a residency program (OR, 2.27; 95% CI, 1.63-3.16) or by a pediatric oncologist (OR, 4.02; 95% CI, 3.03-5.32) were associated with greater enrollment. There was a significant interaction between rurality and hospital size, which had the greatest impact on nonmetropolitan enrollment. Conclusions Clinical trial enrollment was higher among AYAs from nonmetropolitan counties than those from metropolitan counties, predominantly when they were treated at large hospitals.