Efficacy and Safety of CyberKnife-Based SBRT and Linear Accelerator-Based IMRT/VMAT for Thoracic Radiotherapy in Non-Small Cell Lung Cancer: A Propensity Score-Matched Real-World Analysis.

Abstract

IntroductionCyberKnife-based stereotactic body radiotherapy (SBRT) has demonstrated favorable outcomes in multiple tumors. This study aimed to compare the efficacy and safety of CyberKnife-based SBRT versus linear accelerator (LINAC)-based IMRT/VMAT for thoracic radiotherapy in patients with non-small cell lung cancer (NSCLC) in a retrospective study.MethodsIn this retrospective cohort study, we retrospectively analyzed 461 NSCLC patients treated in our hospital. After propensity score matching (PSM), 138 patients (CyberKnife: 46; LINAC: 92) were matched. Median follow-up was 16.4 months (by reverse Kaplan-Meier method), and the short-term local control and early toxicity were compared.ResultsAfter PSM, baseline characteristics were well-balanced. No significant differences were observed in objective response rate (P=0.838), disease control rate (P=0.832), distribution of response categories (P=0.972), or local progression-free survival (Log-Rank P=0.450). However, the CyberKnife group demonstrated superior safety. Symptomatic radiation pneumonitis (RP) (Grade≥2) was significantly lower (6.5% vs. 27.2%; OR=0.214, P=0.004). Notably, no Grade≥2 radiation esophagitis (RE) occurred in the CyberKnife group versus 18.5% with LINAC (P<0.001). Multivariate analyses further confirmed CyberKnife treatment as an independent protective factor against both symptomatic RP (OR=0.208, P=0.021) and symptomatic RE (OR=0.051, P=0.002). Dosimetrically, CyberKnife achieved superior sparing of lung tissue and esophageal tissue (all P<0.001). CyberKnife remained the sole independent predictor for symptomatic RP, while for RE, treatment group (OR=0.068, P=0.041) and esophagus V50_EQD2 (OR=1.073, P=0.019) were independent prognostic factors.ConclusionIn this PSM cohort, CyberKnife and LINAC demonstrated comparable short-term tumor control and local progression outcomes for thoracic radiotherapy in NSCLC. However, CyberKnife was associated with a significantly lower risk of severe radiation-induced toxicities, suggesting a clinically meaningful safety advantage.