SBRT combined with concurrent chemoradiation in stage III NSCLC: Feasibility study of the phase I Hybrid trial

Abstract Purpose To assess the technical and clinical feasibility of the phase I Hybrid trial (NCT01933568), combining SBRT of the primary tumor (PT) and fractionated radiotherapy (FRT) to the lymph nodes (LN). Materials and methods Ten patients with stage III NSCLC with a peripheral PT  Results The Hybrid plans revealed a significant decrease of esophagus EUD n = 0.13, lung V5 and V20 and a significant increase in Dmax of the PRV of the mediastinal envelope. Plans were robust against differential motion of 5 mm between PT and LN in 8 patients and failed in 2 patients due to spinal cord constraints. Average pass rates were ≥87% for EPID dosimetry. Conclusions SBRT and FRT could be combined within the given OAR constraints. Safety will be assessed in the Hybrid trial.