Stereotactic Ablative Radiotherapy for Central Lung Tumors: A Preliminary Study Assessing the Feasibility of Continuous Positive Airway Pressure

INTRODUCTION: Continuous positive airway pressure (CPAP) has been demonstrated to provide favorable physiological changes for lung stereotactic ablative radiotherapy (SABR) delivery. This study investigates its specific utility for central lung tumors. METHODS: O. 4D-CT planning imaging was acquired in standard free breathing and CPAP techniques. Forward-planned 3D conformal SABR plans were generated for both techniques for each patient. Outcomes for analysis included plan selection, planning target volume (PTV) displacement distance from primary central organ at risk (OAR), target volume size, target volume and OAR dosimetry, and qualitative analysis of CPAP tolerability. RESULTS: Twelve of 14 patients tolerated CPAP and underwent CT simulation and planning with standard and CPAP techniques. CPAP plans were preferred in 8 of the 12 patients. The mean PTV-OAR displacement was 5.8 mm (SD = 9.29) with CPAP compared to 4.1 mm (SD = 6.13) with free breathing (p = 0.65). The mean maximum dose to the primary central OAR was 46.4 Gy (SD = 16.9) in the CPAP group and 51.3 Gy (SD = 15.8) in the standard group (p = 0.22). CONCLUSION: CPAP is a safe and well-tolerated treatment adjunct in central lung SABR. Further investigation is required to determine whether CPAP can provide dosimetric advantages.