Racial disparities in lymphoma: Meta-analytic insights into diagnosis and survival gaps

Abstract

Abstract Introduction: Lymphomas constitute a biologically heterogeneous group of clonal lymphocytic proliferations and account for approximately 5% of all malignancies. Historical literature has identified racial disparities in clinical outcomes, with several studies reporting inferior survival among Black patients compared to their White counterparts, although some findings remain inconsistent. Given the ongoing debate, we conducted a comprehensive systematic synthesis to evaluate racial differences in lymphoma diagnostic patterns and survival outcomes. Methodology: This meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included registry-based and observational studies reporting comparative outcomes across racial groups. A comprehensive literature search was performed across five databases; PubMed, Cochrane Library, ClinicalTrials.gov, Embase, and Scopus. The MeSH terms used included: “Health Status Disparities,” “Healthcare Disparities,” “Socioeconomic Factors,” and “Health Equity.” Meta-analyses were conducted using fixed- or random-effects models, based on between-study heterogeneity (I² > 50% indicating substantial heterogeneity). Dichotomous outcomes were summarized as risk ratios (RRs) with corresponding 95% confidence intervals. All statistical analyses were performed using R version 4.5.1. Results: Twenty-four studies met inclusion criteria and were synthesized in the final analysis. Among patients aged >65 years, White individuals had a higher likelihood of lymphoma diagnosis compared to Asians (RR = 1.40; 95% CI: 1.17–1.69; I² = 0%) and Blacks (RR = 1.58; 95% CI: 1.21–2.06; I² = 98.1%). Sex-stratified analyses demonstrated no significant difference in male predominance when comparing Whites to Asians (RR = 1.03; 95% CI: 0.99–1.07) and Blacks (RR = 1.06; 95% CI: 0.99–1.14). In terms of survival outcomes, Whites exhibited superior overall survival compared to Asians (HR = 2.19; 95% CI: 2.05–2.34) and Blacks (HR = 1.58; 95% CI: 1.21–2.06). Relative survival was also marginally higher in Whites compared to Asians (RR = 1.01; 95% CI: 1.00–1.02) and Blacks (RR = 1.10; 95% CI: 1.09–1.12). At initial presentation, Whites were less likely to be diagnosed at Stage I compared to Asians (RR = 0.93; 95% CI: 0.88–0.99), but more likely than Blacks (RR = 1.06; 95% CI: 1.01–1.10). Stage II disease at diagnosis was comparable between Whites and both Asians (RR = 0.88; 95% CI: 0.55–1.41; I² = 70.2%) and Blacks (RR = 0.98; 95% CI: 0.93–1.03; I² = 70%). Stage III disease at diagnosis was statistically comparable between Whites and Asians (RR = 0.68; 95% CI: 0.24–1.88; I² = 96.9%) as well as between Whites and Blacks (RR = 0.95; 95% CI: 0.90–1.00). Histologic subtype analyses revealed no significant difference in follicular lymphoma incidence between Whites and Asians (RR = 1.09; 95% CI: 0.38–3.11; P = 0.503) or Blacks (RR = 1.26; 95% CI: 0.91–1.75). Diagnosis of diffuse large B-cell lymphoma was comparable between Whites and Blacks (RR = 0.93; 95% CI: 0.68–1.27), as was non-Hodgkin lymphoma overall (RR = 0.79; 95% CI: 0.37–1.68). However, Whites had a significantly lower incidence of marginal zone lymphoma compared to Blacks (RR = 0.66; 95% CI: 0.64–0.68; I² = 74%). All-cause mortality was lower among White patients compared to Black patients (RR = 0.81; 95% CI: 0.80–0.83). Conversely, the incidence of B-symptoms was higher in Whites (RR = 1.45; 95% CI: 1.37–1.55). The median number of hospital visits, however, was comparable between groups (RR = 0.96; 95% CI: 0.79–1.18). Conclusion: In this synthesis, White patients constituted a higher proportion of lymphoma diagnoses among individuals aged >65 and demonstrated superior overall and relative survival compared to Black and Asian populations. Despite a higher prevalence of B-symptoms, White patients had lower all-cause mortality and a comparable median number of hospital visits relative to other racial groups. Our study calls for future research to try to unmask the underlying causative factors of racial disparities in these population subgroups. Possible practical directions to resolve the disparities in these subgroups include a thorough evaluation of tumor biology data and an equitable standard of care for all lymphoma patients.