Risk Factors for and Time to Recurrence of Symptomatic Malignant Pleural Effusion in Patients With Metastatic Non-Small Cell Lung Cancer with EGFR or ALK Mutations

Background: The main goal of management in patients with non-small cell lung cancer (NSCLC) and malignant pleural effusion (MPE) is palliation. Patients with MPE and actionable mutations, because their disease is expected to respond quickly and markedly to targeted therapy, are less likely than those without actionable mutations to receive definitive MPE management. Whether such management is indicated in these patients is unclear. Research Questions: What is the time to ipsilateral MPE recurrence requiring intervention in patients with metastatic NSCLC by mutation status? What are the risk factors for MPE recurrence? Study Design and Methods: Retrospective cohort study of consecutive patients who underwent initial thoracentesis for MPE. We used a Fine-Gray subdistribution hazard model to calculate the time to ipsilateral MPE recurrence requiring intervention within 100 days of initial thoracentesis and to identify variables associated with time to pleural fluid recurrence. Results: A total of 396 patients, comprising 295 (74.5%) without and 101 (25.5%) with actionable mutations, were included. Most patients with actionable mutations (90%) were receiving targeted treatment within 30 days of initial thoracentesis. On univariate analysis, patients with actionable mutations showed a significantly higher hazard of MPE recurrence. On multivariate analysis, this difference was not significant. Larger pleural effusion size on chest radiography (P < .001), higher pleural fluid lactate dehydrogenase (P < .001), and positive cytologic examination results (P = .008) were associated with an increased hazard of recurrence. Interpretation: Our findings indicate that patients with actionable mutations have a similar risk of MPE recurrence when compared with patients without mutations and would benefit from a similar definitive management approach to MPE.