Platinum Doublet Chemotherapy and Proton Beam Radiation Therapy in Treating Patients With Stage II-III Non-small Cell Lung Cancer That Cannot Be Removed by Surgery

PRIMARY OBJECTIVE: I. To compare the 1-year progression-free survival rates of 72 gray (Gy) and 60 Gy conventionally fractionated proton beam therapy (PBT) (as part of concurrent combined modality therapy). SECONDARY OBJECTIVE: I. To assess the adverse events, survival, quality of life, and patterns of failure (local regional, distant metastatic) associated with two dose levels of conventionally fractionated PBT (as part of concurrent combined modality therapy). OUTLINE: Patients are randomized to 1 of 2 arms. ARM A: Patients receive platinum based doublet chemotherapy consisting of low dose carboplatin and paclitaxel, standard etoposide cisplatin or carboplatin or standard pemetrexed with cisplatin or carboplatin weekly for up to 6 weeks at the discretion of the treating medical oncologist. Patients also undergo lower dose proton beam radiation therapy daily for a total of 60 Gy for up to 30 weekdays in the absence of disease progression or unacceptable toxicity. ARM C: Patients receive platinum based doublet chemotherapy consisting of low dose carboplatin and paclitaxel, standard etoposide cisplatin or carboplatin or standard pemetrexed with cisplatin or carboplatin weekly for up to 6 weeks at the discretion of the treating medical oncologist. Patients also undergo higher dose proton beam radiation therapy daily for a total of 72 Gy for up to 36 weekdays in the absence of disease progression or unacceptable toxicity. All patients undergo computed tomography (CT) throughout the study, magnetic resonance imaging (MRI) or CT, and positron emission tomography (PET)/CT during screening. After completion of study treatment, patients are followed up every 3 months for 3 years and then every 6 months for 2 years.