3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy

Primary Objective: * Developing Common Toxicity Criteria (CTC) 3.0 grade \> 3 treatment related pneumonitis (TRP) or * Developing local-regional recurrence among patients treated with 3D conformal radiation therapy (CRT) (Arm 1) or intensity modulated radiation therapy (IMRT) (Arm 2). Secondary Objectives: * To assess and compare the time to develop CTC 3.0 grade \> 3 radiation esophagitis in patients with non-small cell lung cancer (NSCLC) treated in arm 1 and arm 2. * To investigate the association of inflammatory cytokines with the time to the development of radiation pneumonitis and outcomes to concurrent chemoradiation between arm 1 and arm 2. * To investigate the association of relevant pharmacogenetics, biomarkers, and gene polymorphisms with the time to the development of radiation pneumonitis and treatment outcomes to concurrent chemoradiation between arm 1 and arm 2. * To evaluate image guided adaptive radiation therapy (IGART) using weekly computed tomography (CT) on rail or cone beam CT in the assessment of tumor response and impact on treatment planning and delivery. * To compare overall survival, progression-free survival, median survival time, in arm 1 and arm 2. * To evaluate the role of functional image of fluorodeoxyglucose-positron emission tomography (FDG-PET) in assessing and predicting the time to the development of TRP and tumor response. * To measure and compare symptom burden over time of the treatment using MD Anderson Symptom Inventory (MDASI)-Lung in the 2 arms. * To determine the impact of comorbid conditions on survival.