Comparing the Outcomes of Stereotactic Ablative Radiotherapy and Non-Stereotactic Ablative Radiotherapy Definitive Radiotherapy Approaches to Thoracic Malignancy: A Systematic Review and Meta-Analysis

Stereotactic ablative body radiotherapy (SABR) is popular because of the high rates of local control with low toxicity seen in lung cancer patients. In this study we compared clinically significant toxicity and overall survival for SABR and non-SABR definitive radiotherapy (conformal radiotherapy) patients. A PUBMED search of all human, English language articles on SABR and non-SABR radically treated early stage lung cancer patients was performed until June 2016. Results of these searches were filtered in accordance with a set of eligibility criteria and analyzed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eighty-seven SABR and 25 non-SABR articles were reviewed. There was no significant difference in pneumonitis rates between patients receiving SABR (11.4%; 95% confidence interval [CI], 9.7-13.3) and non-SABR treatment (14.4%; 95% CI, 10.6-18.8; P = .20). Esophagitis was the most common mediastinal toxicity reported with 15% of all non-SABR patients versus 1% of all SABR patients reporting developing Grade ≥2 toxicity. The proportion of patient surviving at 2 and 3 years was superior for SABR patients (P < .001). Treatment-related deaths were rare (approximately 1% for both treatments). Both radiotherapy approaches had low rates of pneumonitis, mediastinal toxicity, and treatment-related deaths. However, significant heterogeneity in the patient population and study regimens limit the power of direct comparison, showing that further high-quality studies are required to define the role of SABR in higher risk and operable patients.