The survival outcomes and prognosis of stage IV non-small-cell lung cancer treated with thoracic three-dimensional radiotherapy combined with chemotherapy

BACKGROUND: The impact of thoracic three-dimensional radiotherapy on the prognosis for stage IV non-small-cell lung cancer is unclear. This study is to investigate survival outcomes and prognosis in patients with stage IV non-small cell lung cancer (NSCLC) treated with thoracic three-dimensional radiotherapy and systemic chemotherapy. METHODS: Ninety three patients with stage IV NSCLC had received at least four cycles of chemotherapy and thoracic three-dimensional radiotherapy of ≥40 Gy on primary tumors. The data from these patients were retrospectively analyzed. RESULTS: Of the 93 patients, the median survival time (MST) was 14.0 months, and the 1, 2, and 3-year survival rates were 54.8%, 20.4%, and 12.9%, respectively. The MST of patients received radiation dose to primary tumor ≥63Gy and <63 Gy for primary tumor were 15.0 and 8.0 months, respectively (P = 0.001). Patients had metastasis to a single site and lower tumor volume (<170 cm(3)) also produced longer overall survival time (P = 0.002, P = 0.020, respectively). For patients with metastasis at a single site, thoracic radiation dose ≥63 Gy remained a prognostic factor for better overall survival (P = 0.030); patients with metastases at multiple sites, radiation dose ≥63 Gy had a trend to improve overall survival (P = 0.062). A multivariate analysis showed that radiation dose ≥63 Gy (P = 0.017) and metastasis to a single site (P = 0.038) are associated with better overall survival, and the volume of primary tumor was marginally correlated with OS (P = 0.054). CONCLUSIONS: In combination with systemic chemotherapy, radiation dose ≥63 Gy on primary tumor and metastasis to a single site are significant factors for better OS, aggressive thoracic radiotherapy may have an important role in improving OS.