Concurrent Proton and Chemotherapy in Locally Advanced Stage IIIA/B Non-Small Cell Lung Cancer (NSCLC)

Inclusion Criteria: 1. Histologically or cytologically documented NSCLC. 2. Inoperable stage IIIA (T1--3N2MO, T3N1MO) and IIIB (T1-3N3MO, T4NO-3MO) disease excluding malignant pleural effusion. 3. Performance score Karnofsky Performance Status (KPS) 70-100, Weight loss: less or equal to 10% in 6 months prior to diagnosis. 4. Patient consented for the protocol 5. Induction chemotherapy is allowed. Exclusion Criteria: 1. Prior chest radiotherapy. 2. Previous or concomitant malignancy other than (a) curatively treated carcinoma in situ of cervix, (b) basal cell carcinoma of the skin, (c) curatively treated superficial transitional cell carcinoma of the urinary bladder, and (d) early stage tumor treated more than 3 years ago for cure. 3. Pregnancy. Patients (men and women) of child bearing potential should use an effective (for them) method of birth control throughout their participation in this study. 4. Off study criteria: a) If a patient is found to have distant metastasis during treatment and/or immediate after the treatment (\<60 days) indicating inaccurate cancer stage, he or she will be taken off study. b) If a patient does not follow up at MD Anderson and does not forward his or her medical records such as CT, PET/CT, pulmonary function test (PFT) or pathology report as required by protocol, he or she will be taken off study. c) If a patient does not have any required post-treatment evaluation such as images, he or she will be taken off study.