Safety and outcomes of intensity modulated proton therapy in patients with non small cell lung cancer with interstitial lung disease.

The treatment of non-small cell lung cancer (NSCLC) in interstitial lung disease (ILD) remains a challenging clinical scenario. These patients are often not good operative candidates due to poor lung function. Radiotherapy has emerged as a non-operative treatment option for these patients. Proton beam therapy (PBT) offers similar efficacy as photon beam radiotherapy, but with an improved safety profile. We retrospectively reviewed the outcomes of 33 patients with comorbid NSCLC and ILD treated at our institution with intensity modulated proton therapy (IMPT). We evaluated overall survival, recurrence, and radiation pneumonitis. 54 % had Stage I-II disease and 45 % had Stage III-IVA disease. We observed a median overall survival of 1.8 years post-treatment. Cumulative incidence of local recurrence was 21.8 % at two years, and distant recurrence was 36.5 % at two years. Cumulative incidence of grade 2 + radiation pneumonitis was 23.5 % at 12 months. Increased tumor volume and the use of conventional fractionation were associated with decreased overall survival and increased recurrence. Our findings suggest that IMPT is a safe and effective treatment option for NSCLC in patients with ILD.