Phase 1 CyberKnife SBRT uses Synchrony respiratory motion tracking for ultra-central NSCLC

This Phase 1, single-arm Georgetown University study tests whether five-fraction stereotactic body radiation therapy (SBRT) delivered on the Accuray CyberKnife system can safely control ultra-central, node-negative NSCLC. Treatment is 50 Gy in 5 fractions, every other day over approximately 2 weeks, using Synchrony respiratory motion management to follow the target as the patient breathes. Eligible tumors are T1-T2, N0, M0, and patients are medically inoperable or decline surgery.

The primary focus is grade 3 or higher treatment-related toxicity, with local control and longer-term outcomes also tracked. Ultra-central tumors lie close to critical airway or mediastinal structures, where ablative radiation can cause serious airway, vascular, or esophageal injury. Surgery remains an option for operable patients, while carefully planned definitive radiation is used when surgery is unsuitable. The study asks whether real-time tracking can maintain tumor control while reducing severe toxicity near these critical structures.