Racial and socioeconomic disparities in glioblastoma outcomes: A single‐center, retrospective cohort study

Abstract

BackgroundGlioblastoma (GBM) is the most common malignant primary brain tumor. Emerging reports have suggested that racial and socioeconomic disparities influence the outcomes of patients with GBM. No studies to date have investigated these disparities controlling for isocitrate dehydrogenase (IDH) mutation and O‐6‐methylguanine‐DNA methyltransferase (MGMT) status.MethodsAdult patients with GBM were retrospectively reviewed at a single institution from 2008 to 2019. Univariable and multivariable complete survival analyses were performed. A Cox proportional hazards model was used to assess the effect of race and socioeconomic status controlling for a priori selected variables with known relevance to survival.ResultsIn total, 995 patients met inclusion criteria. Of these, 117 patients (11.7%) were African American (AA). The median overall survival for the entire cohort was 14.23 months. In the multivariable model, AA patients had better survival compared with White patients (hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.2–0.69). The observed survival difference was significant in both a complete case analysis model and a multiple imputations model accounting for missing molecular data and controlling for treatment and socioeconomic status. AA patients with low income (HR, 2.17; 95% CI, 1.04–4.50), public insurance (HR, 2.25; 95% CI, 1.04–4.87), or no insurance (HR, 15.63; 95% CI, 2.72–89.67) had worse survival compared with White patients with low income, public insurance, or no insurance, respectively.ConclusionsSignificant racial and socioeconomic disparities were identified after controlling for treatment, GBM genetic profile, and other variables associated with survival. Overall, AA patients demonstrated better survival. These findings may suggest the possibility of a protective genetic advantage in AA patients.Plain Language Summary To best personalize treatment for and understand the causes of glioblastoma, racial and socioeconomic influences must be examined. The authors report their experience at the O’Neal Comprehensive Cancer Center in the deep south. In this report, contemporary molecular diagnostic data are included. The authors conclude that there are significant racial and socioeconomic disparities that influence glioblastoma outcome and that African American patients do better.

Associations between racial categories and outcomes suggest structural causes, not genetic advantages

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We read with interest the article by Estevez-Ordonez and colleagues (published in November 2023) describing disparities in outcomes for patients with glioblastoma (GBM). 1 The rural-urban disparity in GBM outcomes in the study population is indeed an important finding that should lead to efforts to address this inequity. However, we are concerned that the article implies that racial categories are genetically meaningful ways to categorize individuals rather than making it clear that race is a social construct that is, at best, a poor proxy for social and environ-

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“…They note that their observations "may suggest potential racial biologic resilience factors or differences in tumor biology that influence the disease course or response to treatment." 1 It is important to note that the term African American describes a sociopolitical group, not a biological or genetic one, 3 and racial categories are heterogeneous: Individuals in each group can have various exposures and lived experiences.…”

“…4 The authors mention that social determinants could play a role in the disparity but conclude that socioeconomic status (SES) differences did not significantly affect the main outcomes. 1 However, the model does not capture SES adequately, as it uses household income divided into three large categories; this does not adequately capture wealth, a better determinant of health. 5 In addition, other possible environmental exposures could be confounders if they are not equally distributed between the racial groups; the incidence of GBM has long been associated with higher SES, and determining the causal mechanism remains elusive.…”