Identifying the Optimal Radiation Dose in Locally Advanced Non–Small-cell Lung Cancer Treated With Definitive Radiotherapy Without Concurrent Chemotherapy
The optimal radiation dose for locally advanced non–small-cell lung cancer (NSCLC) is not known for patients who receive sequential chemoradiation (CRT) or definitive radiotherapy (RT) only. Our objective was to determine whether a benefit exists for radiation dose escalation for these patients.Materials and Methods
The patients included in our retrospective analysis had undergone RT for NSCLC from 2004 to 2013, had not undergone surgery, and received a dose ≥ 50.0 Gy. Patients who received concurrent CRT were excluded from the analysis, leaving 336 patients for analysis. The primary outcomes were overall survival (OS), local failure (LF), and distant failure (DF).Results
On multivariate analysis, after adjusting for age, Karnofsky performance status, gross tumor volume, and treatment modality, patients treated with a radiation dose > 66 Gy had significantly improved OS compared with those treated with < 60 Gy (hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.39-0.87; P = .008). After adjusting for smoking history and radiologic tumor size, patients treated with a radiation dose > 66 Gy had a significantly decreased risk of LF compared with those treated with < 60 Gy (HR, 0.59; 95% CI, 0.38-0.91; P = .02). The radiation dose was not an independent prognostic factor of DF on multivariate analysis.Conclusion
When controlling for tumor volume and/or dimensions and other independent prognostic factors, patients with locally advanced NSCLC who were not candidates for concurrent CRT benefited from a radiation dose > 66 Gy versus < 60 Gy with improved OS and reduced LF. An increased radiation dose did not appear to affect the incidence of DF.Micro-Abstract
The optimal radiation dose for patients with inoperable, locally advanced non–small-cell lung cancer ineligible for concurrent chemoradiation remains unclear. In the present retrospective, multivariate analysis of 336 patients treated with sequential chemoradiation or definitive radiation only, a radiation dose > 66 Gy was superior to a radiation dose < 60 Gy for the endpoints of overall survival and local failure.