Predictors for spontaneous pleurodesis in patients with indwelling pleural catheters for malignant pleural effusion: a safety net hospital experience

Background: Malignant pleural effusion (MPE) affects approximately 150,000 patients in the United States each year and usually signifies advanced-stage cancer. The optimal treatment remains a challenge but indwelling pleural catheters (IPC) offer several advantages and may help achieve spontaneous pleurodesis (SP) in some patients.Objectives: We aim to investigate the predictors of SP among patients with MPE, particularly in a resource-limited community-based safety net hospital.Design: This is a retrospective cohort study done at a community-based safety net hospital.Methods: Adults diagnosed with or suspected of having MPE between January 2015 and December 2023 who underwent IPC placement were included. Data was collected retrospectively from December 2023 to June 2024. Data encompassed demographics, imaging, post-procedural complications, pleural fluid analysis, oncology treatment history, and utilization of medical thoracoscopy without chemical pleurodesis (MTWCP) for diagnosis.Results: A total of 173 patients underwent IPC insertion. Most of our patients were women (64.2%), and Latin American (65.9%), with a mean age of 55.3 years. The most common type of primary cancer was breast (28.9%) followed by lung (23.1%) and lymphoma (6.9%). Pleural fluid characteristics such as glucose, eosinophils, Lactate Dehydrogenase (LDH), and protein concentration were not significantly associated with SP. Most patients had low Eastern Cooperative Oncology Group scores of 0-2 (64.6%) and low LENT (Lactate Dehydrogenase (L), Eastern Cooperative Oncology Group (E) Performance Score, Neutrophil-to-Lymphocyte Ratio (N), and Tumor type (T) score) scores of 0-4 (59%). Lower scores (better functional status) were significantly associated with SP. Post-IPC chemotherapy and/or radiotherapy and immunotherapy were significantly associated with SP, adjusted odds ratio (OR) 7.295 (95% CI: 3.05-17.4, p = 0.001) and adjusted OR 6.261 (95% CI: 2.73-14.36, p = 0.001) respectively. MTWCP was also a predictor of SP with an adjusted OR of 4.031 (95% CI: 1.452-11.19, p = 0.007).Conclusion: Our study is the first to assess predictors of SP in a resource-limited safety net hospital representing under-represented and underserved patients. We identify several factors associated with higher rates of SP such as higher functional status, MTWCP, chemotherapy, immunotherapy, and radiation post-IPC placement. The study findings can help clinicians consider IPC placement and guide them regarding the duration and possible complications of IPC. MTWCP appears to improve the success of SP. Further studies are needed to assess these findings further.