Could a common heartburn drug shield lung cancer patients from radiation side effects?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patient is ≥ 18 years of age. * Patient or patient's legal representative is willing and able to provide written informed consent and HIPAA authorization prior to performance of any study related activity. * Patient is willing and able to comply with scheduled visits and treatment schedules. * Patient has histopathologically confirmed diagnosis of NSCLC clinical stage III (as per the 8th edition of American Joint Committee on Cancer Staging). * Patients will receive thoracic radiation with estimated maximum dose to esophagus of at least 30 Gy (EQD2) in combination with concomitant chemotherapy. * Patient has Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 2. * Women of childbearing potential (WOCBP) must have a negative pregnancy test (serum or urine HCG) within 2 weeks of enrollment). * Double inclusion in any ongoing trial (if the other trial permits) will be allowed. Exclusion Criteria: * Patient has history of gastroesophageal junction or stomach cancer. * Patient has history of pre-existing severe or very severe dysphagia. * Patient has history of severe liver disease, acute or subacute systemic lupus erythematosus. * Patient has interstitial nephritis. * Patient has history of peptic ulcer disease. * Patient has prior history of upper gastrointestinal bleeding. * Patient has a history of thoracic radiotherapy within 2 years of enrollment. * Patient has known or suspected allergic response and prior adverse drug reaction with proton pump inhibitors. * Patient is currently on clopidogrel, nelfinavir, rilpivirine, methotrexate, rifampin, digoxin, tacrolimus, or phenytoin as these may have major drug interaction with esomeprazole. * Patients without concomitant chemoradiotherapy and with estimated maximum dose to esophagus of less than 30 Gy (EQD2).