Enrollment will begin with a phase I lead in evaluating radiation therapy with durvalumab (MEDI 4736). (Regimen A) to ensure general safety of this combination and specifically relating to pulmonary toxicity (pneumonitis), cardiac toxicity (pericarditis) and gastrointestinal toxicity (esophagitis, gastritis, enterocolitis). Following initial demonstration of safety, enrollment to the phase II component with 1:1 randomization to radiation therapy and durvalumab (MEDI 4736), (Regimen A) or radiation therapy alone (Regimen B) will be performed with stratification only based on T-stage (Tumor) (T1 versus T2). A total of 90 patients will be randomized in the phase II component.