A Comparative Study of Patients With Early-Stage Non-Small Cell Lung Cancer Treated With Stereotactic Body Radiation Therapy Using CyberKnife and Linear Accelerator–Based Volumetric Modulated Arc Therapy

Stereotactic body radiation therapy (SBRT) has become the standard of care for medically inoperable early-stage non-small cell lung cancer. We investigated 2 modalities of lung SBRT, CyberKnife (CK) and volumetric modulated arc therapy (VMAT), for differences in dosimetric parameters, tumor control, and clinical outcomes.Patients who underwent SBRT for T1-2N0M0 non-small cell lung cancer from 2012 to 2018 were included. Dosimetric parameters for target volume coverage and organ-at-risk dose distribution were collected. Survival outcomes were evaluated using the Kaplan-Meier method with log-rank test. A multivariate Cox proportional hazards model was analyzed for local, regional, and distant tumor control; overall survival (OS) and progression-free survival; and radiation pneumonitis.Two hundred twenty-seven patients (142 CK, 85 VMAT SBRT) met inclusion criteria. Overall, the local, regional, and distant control rates were 89.3%, 86.3%, and 87.4% at 2 years, and the OS was 67.5% and 32.8% at 2 and 5 years, respectively. VMAT delivered higher maximum doses to the gross tumor volume and planning target volume and had a lower lung and heart V5. Although there was no difference in local or distant failure, progression-free survival, or OS, VMAT was associated with superior freedom from regional failure (adjusted hazard ratio, 0.26; P = .045). With no difference between treatment modalities, 11.9% of patients developed grade 1 to 2 radiation pneumonitis. There were no grade 3+ events of radiation pneumonitis.This study revealed that VMAT and CK provided comparable local and distant control and survival outcomes; however, VMAT exhibited better regional control. Further study in this regard is imperative.