Personalized Escalation of Consolidation Treatment Following Chemoradiotherapy and Immunotherapy in Stage III NSCLC in Stage III NSCLC

This study uses a blood test for tumor DNA (ctDNA) to guide how much additional treatment people with stage III non-small cell lung cancer (NSCLC) should receive after standard chemoradiation and immunotherapy (durvalumab). If ctDNA is found in the blood, additional therapy may be added. **You may be eligible if...** - You are 18 years old or older - You have stage III NSCLC or locally recurring lung cancer that has been treated with chemotherapy and radiation - You are currently receiving consolidation durvalumab (immunotherapy) after completing chemoradiation - Less than 32 weeks have passed since your first durvalumab dose - You are in good general health (ECOG performance status 0 or 1) - Your blood counts and organ function are within acceptable ranges **You may NOT be eligible if...** - Your lung cancer has progressed during or after initial treatment - You have previously had immunotherapy other than as part of this study - You have serious autoimmune disease or other conditions that prevent participation - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.