Image-Guided, Intensity-Modulated Photon or Proton Beam Radiation Therapy in Treating Patients With Stage II-IIIB Non-small Cell Lung Cancer

Inclusion Criteria: * Pathologically proven diagnosis of unresected stage II-IIIB, or recurrent after surgical resection or stereotactic body radiation therapy (SBRT) non-small cell lung cancer * Suitability for concurrent chemoradiation therapy per treating physician's assessment * Karnofsky performance status (KPS) score \>= 70 * Weight loss \< 15% in the 3 months before diagnosis * Prior receipt of induction chemotherapy followed by referral for concurrent chemoradiation is allowed * Adequate lung function indicated by forced expiratory volume at 1 second (FEV1) \>= 1 L is required * The primary tumor and/or regional lymph nodes must be evaluable radiographically * The gross target volume (GTV) is suitable for motion management using 4 dimensional computed tomography (4D CT), internal target volume (ITV), or respiratory gating; in addition, the target coverage and normal tissue constraints must be met as specified in protocol accounting for the respiratory motion of anatomy as a whole (not just the tumor) * No prior radiation to the mediastinal structures * Hemoglobin \>= 9.0 g/dL * Absolute neutrophil count (ANC) \>= 1,500/mm\^3 * Platelet count \>= 100,000/mm\^3 * Total bilirubin =\< 1.5 times the upper limit of normal (ULN) * Alanine and aspartate transaminases (ALT and AST) =\< 2.5 times the ULN (=\< 5 x ULN for patients with liver involvement) * Creatinine =\< 1.5 times ULN * Patients must sign an informed consent indicating that they are aware of the investigational…