Preliminary Results of Proton-Beam Therapy for Stage iii Non-Small-Cell Lung Cancer

Background: We conducted a preliminary retrospective evaluation of the efficacy and toxicity of proton-beam therapy (pbt) for stage iii non-small-cell lung cancer. Methods: Between January 2009 and August 2013, 27 patients (26 men, 1 woman) with stage iii non-small-cell lung cancer underwent pbt. The relative biologic effectiveness value of the proton beam was defined as 1.1. The beam energy and spread-out Bragg peak were fine-tuned such that the 90% isodose volume of the prescribed dose encompassed the planning target volume. Of the 27 patients, 11 underwent neoadjuvant chemotherapy. Cumulative survival curves were calculated using the Kaplan–Meier method. Treatment toxicities were evaluated using version 4 of the Common Terminology Criteria for Adverse Events. Results: Median age of the patients was 72 years (range: 57–91 years), and median follow-up was 15.4 months (range: 7.8–36.9 months). Clinical stage was iiia in 14 patients (52%) and iiib in 13 (48%). The median dose of pbt was 77 GyE (range: 66–86.4 GyE). The overall survival rate in the cohort was 92.3% at 1 year and 51.1% at 2 years. Locoregional failure occurred in 7 patients, and distant metastasis, in 10. In 2 patients, initial failure was both locoregional and distant. The 1-year and 2-year rates of local control were 68.1% and 36.4% respectively. The 1-year and 2-year rates of progression-free survival were 39.9% and 21.4% respectively. Two patients experienced grade 3 pneumonitis. Conclusions: For patients with stage iii non-small-cell lung cancer, pbt can be an effective and safe treatment option.