Neighborhood social vulnerability and clinical trial enrollment in colon cancer: Does age matter?

Abstract

1533 Background: Colorectal cancer is now the leading cause of cancer-related death in people under 50, and young adults living in poverty have increased mortality. Despite younger age being associated with higher clinical trial enrollment, young adults face distinct social and structural barriers that may impede participation. This study examines how neighborhood social vulnerability is associated with clinical trial participation for colon cancer in young and older adults. Methods: Patients diagnosed with colon cancer were identified in the nationally representative Vizient Clinical Database from January 2022 – June 2025 and stratified into young adult (age 18-49) and older adult (50 and above) cohorts. The outcome of interest was clinical trial enrollment, identified by billing codes. Social vulnerability was defined by the Vizient Vulnerability Index in quartiles at the census tract level. Multivariable analyses were performed in both cohorts. An interaction analysis was performed between age and social vulnerability. Results: Of 234,047 patients, 15% were young adults, of which 5.1% enrolled in a clinical trial. Eighty-five percent were older adults, of which 3.0% enrolled in clinical trials. Most young adults had private insurance (73.1%) while most (56.6%) of the older patients were enrolled in Medicare. Non-Hispanic (NH) Black patients were less likely to enroll than NH White patients in both the young adult (OR 0.72, p=0.0001) and older adult cohorts (OR 0.79, p<.0001), as were young and older patients with Medicaid vs. private insurance (OR 0.75, p=0.0001 and OR 0.71, p<.0001, respectively). Diagnosis at an academic medical center vs. community hospital increased the odds of enrollment for both groups: young (OR 2.79, p<.0001) and older (OR 2.04, p<.0001), as did being married vs. single: OR 2.31, p=0.0016 for younger and OR 1.85, p<.0001 for older adults. Among older adults only, Hispanic patients (OR 0.87, p=0.0056; ref NH White) and female patients (OR 0.91, p=0.0002; ref male) were less likely to enroll. Living in the most vs. least socially vulnerable neighborhoods impacted trial enrollment more for young adults (OR 0.75, p<.001) than for older adults (OR 0.91, p<.0001), p= 0.0042 for interaction. Conclusions: Many factors that influence trial enrollment, including insurance, social support, diagnosis at an academic center, and race/ethnicity, are similar among young and older adults with colon cancer. However, the negative impact of neighborhood disadvantage on trial enrollment is more pronounced among young adults, highlighting the need for practical trial design, targeted navigation, and strategic recruitment of young adults living in socially vulnerable areas.