A Phase I/II Study of Hypofractionated Proton Therapy for Stage II-III Non-Small Cell Lung Cancer

Conventional fractionated photon-based radiotherapy to 60-63 Gy at 1.8-2 Gy/fraction with concurrent chemotherapy remains the standard treatment practice in patients with stage III non-small cell lung carcinoma (NSCLC) with local control rates of approximately 50% and a median overall survival of just 18 months.Unfortunately, even the standard treatment has significant toxicity with approximately 40% of patients developing grade 3 or higher acute toxicities in the RTOG 9410 study.1 These outcomes are poor and more effective treatment regimens are needed. Higher doses of radiation have been hypothesized to improve local control in patients with stage III NSCLC. This is expected to translate into better overall survival.Given the significant improvements in outcome in patients receiving hypofractionation for stage I NSCLC, perhaps similar gains could be achieved if hypofractionated radiotherapy could be safely delivered to stage II-III NSCLC with concurrent chemotherapy. Hypofractionated radiotherapy may offer improvement in local control compared with conventional fractionation that may translate into improved overall survival. Furthermore, hypofractionation will shorten the time interval during which patients are receiving less aggressive chemotherapy. Proton therapy is a highly conformal radiotherapy technique that takes advantage of the proton's characteristic Bragg Peak, resulting in significant reductions in the exit dose of the treatment beam. Thus, proton therapy can substantially reduce the dose to critical structures even compared with IMRT. This study will investigate the safety and efficacy of delivering hypofractionated proton therapy with concurrent chemotherapy in patients with stage II-III NSCLC