Disparities in the enrollment to systemic therapy and survival for patients with multiple myeloma

Background: Disparities driven by socioeconomic factors have been shown to impact outcomes for cancer patients. We sought to explore this relationship among patients with multiple myeloma (MM) who were not considered for hematopoietic stem cell transplant in the first-line setting and how it varied over time. Methods: We queried the National Cancer Database for patients diagnosed with MM between 2004 and 2016 and included only those who received systemic therapy as the first-line treatment. Enrollment rates for therapy were calculated as receipt of systemic therapy as the incident event of interest (numerator) over time to initiation of therapy (denominator) and used to calculate incident rate ratios that were further analyzed using Poisson regression analysis. A multivariate Cox proportional hazards model was constructed for survival analysis, and differences were reported as hazard ratios (HRs). Results: We identified 56,102 patients for enrollment analysis and 50,543 patients for survival analysis. Therapy enrollment in a multivariate model was significantly impacted by race and sex (p < .005). Advanced age, earlier year of diagnosis, lack of insurance or Medicaid, and higher comorbidity were associated with poor survival (HR > 1), whereas female sex, non-Hispanic black race, higher income, and treatment at an academic center were associated with improved survival (HR < 1). Conclusion: Disparities in treatment of MM exist and are caused by a complex interplay of multiple factors, with socioeconomic factor playing a significant role. Studies exploring such determinants may help in equitable distribution of resources to overcome such differences.