Background: There have been tremendous advancements in Non-Hodgkin Lymphoma (NHL) therapies and outcomes in large part due to clinical trials. Prior studies have demonstrated that certain populations including the elderly, certain racial and/or ethnic minority groups, and women are underrepresented in cancer clinical trials. Better understanding of how social context impacts clinical trial enrollment will allow us to better design tailored interventions to address barriers to clinical trial participation. We performed a retrospective analysis of patients with NHL seen at MD Anderson Cancer Center (MDACC) to systematically investigate the association between clinical trial participation patterns and sociodemographic context measured by neighborhood socioeconomic factors based on place of residence. Examining our practice patterns may then inform strategies to enhance trial recruitment of underrepresented groups. Methods: We examined 3448 patients, age ≥18 years with a diagnosis of NHL seen at MDACC between January 2017 and December 2020. Using patient address, geolocation software and American Community Survey (2015 - 2020) and 2020 census data available through data.Census.gov we ascertained 35 neighborhood level socioeconomic status (nSES) variables corresponding to each census tract including the domains of educational attainment, neighborhood median income, poverty, crowding, race composition and home values. We performed descriptive analysis to understand the demographics of the total populations and those enrolled in clinical trials. We performed univariate analysis of clinical trial enrollment patterns by sex, race, age, histology type, insurance type and nSES variables using 2-sample t-test and Mann-Whitney tests (MHT). Using exhaustive variable selection based upon minimizing the Akaike Information Criteria, including 2-way interactions, we found the set of variables that generated an optimal generalized additive logistic regression model for incidence of participation in clinical trials. We repeated this procedure for the diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) subgroups. We adjusted alpha 0.05/3=0.017 as the criteria for significance in these models to address multiple testing. Results: We excluded 130 patients with international patient addresses and 427 patients without complete address information. and found no significant difference in baseline characteristic or clinical trial enrollment between the 572 excluded patients and the study cohort of 2943 patients. The study population was 59% male, 74.6% Non-Hispanic white (NHW), 13.2% Hispanic, 6.1% black, 3.7% Asian; 29.5% had DLBCL, 22% FL, 13.2% mantle cell, 9% marginal zone, 8.3% T-cell, and 6.5% high grade B cell lymphoma. The most common insurance was managed care 47% and Medicare 45.7%; 2.5% of patients were self-pay, 1.2% had Medicaid, and 2.1% had other government insurance. There was a high overall clinical trial participation rate of 30.5% with 20.9% enrolled in therapeutic trials and participation differed by diagnosis (Table). In univariate analyses, lower participation rates were associated with lower nSES including: increasing % of populations living below poverty level, increasing % living in crowded households, increasing % above age 25 years with less than high school diploma, and decreasing median household income. Racial composition of census tract was not associated with differences in clinical trial participation. Participation did not differ by insurance type. In multivariable analysis, incidence of participation declined nonlinearly with age in the overall, FL, and DLBCL models. In the DLBCL subset Hispanic patients had lower odds of participation than Whites (odds ratio 0.34, p=0.0003). No nSES variable predicted clinical trial participation in these models. Conclusion: In a large academic cohort, age and diagnosis not race, gender, insurance type, or nSES were independent predictors of trial participation. One major limitation to the generalizability of these results is the select patient population seen at our institution are relatively well insured. Examination of multi-center datasets including community practices when underinsured patients received care and evaluation of interventions to influence access to clinical trials are needed. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal