Stereotactic Body Radiotherapy for Centrally Located Primary Non-Small-Cell Lung Cancer: A Meta-Analysis

Abstract

The feasibility of stereotactic body radiotherapy (SBRT) for centrally located tumors is controversial. SBRT with 100 Gy or higher biologically equivalent dose using an alpha/beta of 10 Gy for centrally located primary NSCLC offered excellent local control (3years; 77.6% [95% confidential interval, 65.2-86.5]), comparable with that of other SBRT reports for peripheral lung tumors. The pooled rate of Grade >= 3 complications was 12.0%. This suggest that SBRT can be used in inoperable centrally located lung tumors with a curative intent. Background: The purpose of the study was to evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) for centrally located, primary non-small-cell lung cancer (NSCLC). Materials and Methods: Systematic search of 4 databases (PubMed, MEDLINE, EMBASE, and Cochrane Library) was performed for literature published until May 9, 2018. Primary (overall survival [OS] and local control [LC] rates) and secondary (Grade >= 3 toxicity) endpoints were reported. Results: Thirteen studies encompassing 599 patients with central NSCLCs were included. Median values of T1 tumor proportion, tumor size, and median survival were 55.3% (range, 0%-75%), 3.3 (range, 2.1-4.1) cm, and 26 (range, 14-68.9) months, respectively. Pooled rates of 1-, 2-, and 3-year OS rates were 84.3% (95% confidence interval [CI], 75.7-90.3), 64.0% (95% CI, 52.9-72.2), and 50.5% (95% CI, 39.4-61.5), respectively. Pooled rates of 1-, 2-, and 3-year LC rates were 89.4% (95% CI, 80.8-94.4), 82.2% (95% CI, 71.7-89.4), and 72.2% (95% CI, 55.0-84.7), respectively. Pooled rate of Grade >= 3 complication was 12.0% (95% CI, 7.3-19.0). Meta-regression analyses showed significant positive relationships between biologically equivalent dose using an alpha/beta of 10 Gy in the linear quadratic model (BED10Gy) and 1- and 2-year LC rates (P < .001 and P < .001), and 1- and 2-year OS rates (P = .0178 and P = .032), and Grade >= 3 complication rate (P = .0029). In subgroup comparisons between BED10Gy < 100 Gy versus >= 100 Gy, 1- and 2-year LC rates were significantly different but not for OS and Grade >= 3 complication rates. Conclusion: Our results suggests that SBRT is potent for tumor control in central NSCLC, although complications should be further minimized through optimization of dose-fractionation scheme and accurate planning. Using BED10Gy >= 100 Gy yielded higher LC rates, and dose escalation was related to OS, LC, and complications. (C) 2019 Elsevier Inc. All rights reserved.