Abstract
BACKGROUND AND PURPOSE: There is no consensus on the best photon radiation technique for non-small cell lung cancer (NSCLC). This study quantified the differences between commonly used treatment techniques in NSCLC to find the optimal technique. MATERIALS AND METHODS: Treatment plans were retrospectively generated according to clinical guidelines for 26 stage III NSCLC patients using intensity modulated radiation therapy (IMRT), hybrid, and volumetric modulated arc therapy (VMAT(C), and VMAT(V5) optimized for lower lung and heart dose). Plans were evaluated for target coverage, organs at risk dose (including heart substructures) and normal tissue complication probabilities (NTCP). RESULTS: The comparison showed significant and largest median differences (>1 Gy or >5%) in favor of IMRT for the mediastinal envelope and heart (maximum dose), in favor of the hybrid technique for the lungs (V5Gy of the total lungs and V5Gy of the contralateral lung) and in favor of VMAT(C) for the heart (Dmean), most of the substructures of the heart, and the spinal cord (maximum dose). The VMAT(V5) technique had significantly lower heart dose compared to the hybrid technique and significantly lower lung dose compared to the VMAT(C), combining both advantages in one technique. The mean ΔNTCP did not exceed the 2 percent point (pp) for grade 5 (mortality), and 10 pp for grade ≥2 toxicities (radiation pneumonitis and acute esophageal toxicity), but ΔNTCP was mostly in favor of VMAT(C/V5) for individual patients. CONCLUSION: This planning study showed that VMAT(V5) was preferred as it achieved low lung and heart doses, as well as low NTCPs, simultaneously.