Disparities in Survival Due to Social Determinants of Health and Access to Treatment in US Patients with Operable Malignant Pleural Mesothelioma

Abstract

Importance: Outcomes of localized malignant pleural mesothelioma (MPM) remain poor despite multimodality therapy. It is unclear what role disparities have in the overall survival (OS) of patients with operable MPM. Objective: To examine survival disparities associated with social determinants of health (SDOHs) and treatment access in patients with malignant pleural mesothelioma. Design, Setting, and Participants: In this observational, retrospective cohort study, patients with MPM diagnosed between January 1, 2004, and December 31, 2017, were identified from the National Cancer Database with a maximum follow-up time of 13.6 years. The analysis was conducted from February 16, 2022, to July 29, 2022. Patients were included if they were diagnosed with potentially resectable clinical stage I to IIIA MPM, had epithelioid and biphasic histologic subtypes, and received chemotherapy. Patients were excluded if they could not receive curative surgery, were 75 years or older, or had metastasis, unknown stage, or tumor extension to the chest wall, mediastinal tissues, or organs. Exposures: Chemotherapy alone vs chemotherapy with curative surgery in the form of pleurectomy and decortication or extrapleural pneumonectomy. Main Outcomes and Measures: The primary end point was OS. Cox proportional hazards regression models were used to determine hazard ratios (HRs) for OS, including univariable and multivariable models controlling for potential confounders, including demographic, comorbidity, clinical, treatment, tumor, and hospital-related variables, as well as SDOHs. Results: A total of 1389 patients with MPM were identified (median [IQR] age, 66 [61-70] years; 1024 [74%] male; 12 [1%] Asian, 49 [3%] Black, 74 [5%] Hispanic, 1233 [89%] White, and 21 [2%] of other race). The median OS was 1.7 years (95% CI, 1.6-1.8). Risk factors associated with worse OS included older age, male sex, Black race, low income, and low educational attainment. Factors associated with greater odds of survival included receipt of surgical therapy, recent year of treatment, increased distance to travel, and treatment at high-volume academic hospitals. The risk factors most strongly associated with poor OS included Black race (HR, 1.96; 95% CI, 1.43-2.69) and male sex (HR, 1.60; 95% CI, 1.38-1.86). Surgical treatment in addition to systemic chemotherapy (HR, 0.70; 95% CI, 0.61-0.81) was independently associated with improved OS, as were chemotherapy initiation (HR, 0.93; 95% CI, 0.87-0.99) and greater travel distance from the hospital (HR, 0.92; 95% CI, 0.86-0.98). Conclusions and Relevance: In this retrospective cohort study of patients with operable MPM, there was significant variability in access to care by SDOHs. Addressing disparities in access to multimodality therapy can help ensure equity of care for patients with MPM..