Impact of interstitial changes on radiation pneumonitis after stereotactic body radiation therapy for lung cancer

Aim: The aim of the present study was to evaluate the impact of interstitial changes (IC) on radiation pneumonitis (RP) after stereotactic body radiation therapy (SBRT) for lung cancer. Patients and Methods: We analyzed 260 consecutive patients with primary lung cancer treated with SBRT. According to the presence or absence of IC on the pre-treatment computed tomography, patients were divided into two groups: an IC group (n=18) and a non-IC group (n=242). Results: RP of grade 2 or more was observed in 9 (50.0%) and 14 (6.7%) patients in the IC and non-IC group, respectively. All three patients with grade 5 RP were in the IC group. As indicated by multivariate analysis, the presence of IC was the only significant predictive factor of RP of grade 2 or more. Conclusion: The presence of IC was a significant indicator of grade 2 or more RP after SBRT for patients with lung cancer.