Intensity-modulated radiation therapy versus volumetric-modulated arc therapy in non-small cell lung cancer : assessing the risk of radiation pneumonitis

Abstract

Purpose: This study aimed to compare intensity-modulated radiation therapy (IMRT) and volumetricmodulated arc therapy (VMAT) regarding plan quality and healthy lung sparing, in stage III non-small cell lung cancer (NSCLC) patients. Materials and methods: The plans of 60 patients were allocated either to the IMRT (n=30) or the VMAT (n=30) group. The dose prescribed to the planning target volume (PTV) was evaluated at the 95% level and the mean lung dose (MLD) and the healthy lung receiving 5, 10 and 20 Gy (V5, V10 and V20, respectively) were analysed. The normal tissue complication probability (NTCP) for radiation pneumonitis was calculated with the Lyman–Kutcher–Burman model. Results: Both techniques achieved comparable results for target coverage (V95%=97.87 versus 97.18%, p>0.05) and homogeneity. The MLD (15.57 versus 16.98 Gy, p>0.05), V5 (60.35 versus 67.25%, p>0.05) and V10 (45.22 versus 53.14%, p=0.011) were lower for IMRT, whereas VMAT reduced V20 (26.44 versus 25.90%, p>0.05). The NTCP for radiation pneumonitis was higher for VMAT, but no statistical significance was observed (11.07 versus 12.75, p>0.05). Conclusion: Both techniques seemed suitable for NSCLC treatment, but IMRT presented better results regarding lung sparing thus being beneficial in reducing the risk of radiation-induced pneumonitis.