Elimination of PTV Margins Based on Online Adaptive Stereotactic Radiotherapy for Centrally Located Early-stage Non-small Cell Lung Cancer

This study is testing an adaptive radiation therapy technique for people with early-stage lung cancer located near the center of the chest (centrally located). By using real-time imaging to adapt the radiation field each session, doctors may be able to safely eliminate safety margins around the tumor, potentially reducing side effects to nearby healthy tissue. **You may be eligible if...** - You have confirmed early-stage non-small cell lung cancer (T1-2N0M0) or locally recurrent early-stage NSCLC that cannot be surgically removed (or you choose not to have surgery) - Your tumor is centrally located in the lung - You are 18 or older in good to moderate health (ECOG 0-2) - Your blood counts, kidney, and liver function are within required ranges - Your lung function (FEV1) is at least 0.5 liters **You may NOT be eligible if...** - You have an active infection, had a heart attack within 6 months, or have uncontrolled heart disease - You are pregnant or breastfeeding - You have a substance abuse disorder, chronic alcoholism, or AIDS - You have uncontrolled seizures or severe psychiatric conditions - You have a history of severe allergies Talk to your doctor to see if this trial is right for you.