Abstract B162: Disparities in care for malignant pleural effusion: A real-world analysis in cancer

Abstract Background: Malignant pleural effusion (MPE) remains a devastating complication of advanced cancer, disproportionately affecting patients with lung cancer. Since 2016, the emergence of immune checkpoint inhibitors and novel systemic therapies has transformed the standards of care; however, it is unclear whether these advances have equitably reached all patient populations. Real-world disparities in access to MPE treatments are poorly understood, particularly in the context of rapid therapeutic innovation. Robust data are urgently needed to inform equitable cancer care delivery across diverse clinical and sociodemographic groups. Methods: We conducted a retrospective, cross-sectional analysis of 7,411 adult patients with cancer-associated MPE from 2016–2025 at a large academic center, identified via ICD-10 coding. Demographic, clinical, and treatment variables included age, gender, race, smoking history, primary payor, vital status, and receipt of thoracentesis, pleurodesis, immune checkpoint inhibitor (ICI), and platinum chemotherapy. Patients were stratified by tumor origin (lung vs non-lung) and treatment combinations to assess disparities in interventions and outcomes. Results: Among all MPE patients, 2,836 (38.3%) had lung cancer. Compared to non-lung MPE, lung MPE patients were younger (median 67 vs 70), had higher mortality (71.3% vs 57.1%), and lower survival at cutoff (28.4% vs 42.6%). Lung MPE patients had greater ICI and platinum use but markedly low pleurodesis rates (2.6%) even among those on systemic therapy. Among 803 ICI-treated lung MPE patients, 73.6% received platinum. ICI-only patients were older, had higher mortality, and lower pleurodesis use. Never-smokers (n=535) were predominantly female (69%) and had 70% mortality, suggesting potential enrichment for oncogene-driven disease. Medicaid and Black patients had higher mortality and were underrepresented in ICI+platinum groups, while commercially insured patients had greater access to both systemic therapy and pleurodesis. Procedure rates and treatment intensity varied substantially by race, age, payor, and smoking status. Conclusions: This real-world analysis demonstrates substantial disparities in MPE care. Medicaid and Black patients were consistently less likely to receive ICI+platinum therapy and pleurodesis, and had higher mortality, while commercially insured patients received more advanced and guideline-concordant care. These findings underscore systemic inequities that remain underexplored in MPE-specific research. Despite evolving standards of care, pleurodesis was performed in only 2.6% of lung MPE patients, highlighting a concerning disconnect from guidelines recommending local control. The high mortality among never-smokers—particularly women—adds urgency to expanding access to molecular testing and precision therapies. Together, these findings identify actionable gaps in the delivery of equitable, palliative, and life-extending care for lung cancer patients with MPE, supporting the need for targeted health policy and quality improvement interventions. Citation Format: Abner A. Murray, Nehemias Guevarra. Disparities in care for malignant pleural effusion: A real-world analysis in cancer abstract. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr B162.