Abstract
BACKGROUND: EGFR-mutant (EGFR-M) and ALK-positive (ALK-P)are common in malignant pleural effusion (MPE) with metastatic non-small-cell lung cancer (NSCLC) (MPE-NSCLC). The impact of thoracic tumor radiotherapy on survival in such patients remains unclear. We aimed to investigate whether thoracic tumor radiotherapy could improve overall survival (OS) in such patients. METHODS: According to whether or not patients accepted thoracic tumor radiotherapy, 148 patients with EGFR-M or ALK-P MPE-NSCLC treated with targeted therapy were classified into two groups: DT group without thoracic tumor radiotherapy and DRT group with thoracic tumor radiotherapy. Propensity score matching (PSM) was performed to balance clinical baseline characteristics. Overall survival was analyzed by Kaplan-Meier, compared by log-rank test, and evaluated using Cox proportional hazards model. RESULTS: Median survival time (MST) was 25 months versus 17 months in the DRT group and DT group. The OS rates at 1, 2, 3, 5 years in the DRT group and DT group were 75.0%, 52.8%, 26.8%, 11.1% and 64.5%, 28.4%, 9.2%, 1.8%, respectively (χ(2) = 12.028, p = 0.001). Compared with DT group, the DRT group still had better survival after PSM (p = 0.007). Before and after PSM, factors associated with better OS through multivariable analysis were that thoracic tumor radiotherapy, radiotherapy, N(0-2) , and ALK-TKIs. Grades 4-5 radiation toxicities were not observed in patients; 8 (11.6%) and 7 (10.1%) out of the DRT group suffered from Grade 3 radiation esophagitis and radiation pneumonitis, respectively. CONCLUSION: Our results for EGFR-M or ALK-P MPE-NSCLC showed that thoracic tumor radiotherapy may be crucial factor in improving OS with acceptable toxicities. Potential biases should not be neglected: Further randomized controlled trials are necessary to confirm this result.