The survival impact of multimodal therapy in Masaoka stage IV thymic tumors

Abstract

Background: Thymic tumors are the most frequent anterior mediastinal tumors. However, no randomized clinical trials provide definitive treatment guidance for the management of Masaoka stage IV patients. The aim of this study is to determine the values of multimodal therapy in Masaoka stage IV thymic tumors. Methods: We retrospectively studied 26 patients with Masaoka stage IV thymic tumors that were diagnosed between 2006 and 2014. Twenty-two patients were treated with surgical resection, postoperative irradiation, and adjuvant cisplatin-based chemotherapy. The remaining four patients with inoperable diseases were given radiotherapy and/or chemotherapy. Thymic carcinomas were found in 17 patients. Stage IVa disease occurred in 9 patients (pleural dissemination: 6, pericardial dissemination: 3); while the remaining 17 were stage IVb disease. Radiation dose was escalated to 60–66 Gy if the gross disease had been noted. Total radiation doses ranged from 50 to 66 Gy. Results: For all patients, the survival rates were 69.2% for 5-year overall survival, 38.5% for progression-free survival, and 57.7% for locoregional recurrence-free survival. The median survival was 49.98 months (range, 5.93–138.57 months) and the median progression-free survival was 28.83 months (range, 2.33–121.33 months). For 17 patients with thymic carcinomas, the survival rates were 58.8% for 5-year overall survival, 41.2% for progression-free survival, and 58.8% for locoregional recurrence-free survival. Their median survival was 45.07 months (range, 3.53–121.33 months) and the median progression-free survival was 16.73 months (range, 2.33–121.33 months). The predictor of progression-free and locoregional recurrence-free survival was the surgical intervention (surgery vs. biopsy only, P Conclusions: Multimodal therapy improved the survival outcome of patients with stage IV thymic tumors. Surgical resection (including debulking surgery) was the key contributor of progression-free survival and locoregional control.