A Multicenter Phase II Study of Stereotactic Radiotherapy for Centrally Located Lung Tumors (STRICT-LUNG STUDY) and Ultra-centrally Located Lung Tumors (STAR-LUNG STUDY).

This study is testing focused, high-precision radiation therapy (stereotactic body radiotherapy, or SBRT) for lung tumors located near critical structures like the airway, esophagus, heart, or spinal cord — places where standard SBRT is considered more risky. The study includes two groups: "central" tumors (near major airways) and "ultra-central" tumors (directly touching the main airway). **You may be eligible if...** - You are over 18 years old with biopsy-proven or clinically evident non-blood cancer with local progression - Your tumor is 5 cm or smaller and is located near or touching central airway or critical structures - You are unable to have surgery or have refused it - You have a life expectancy greater than 6 months - All other cancer sites are treated or planned for treatment **You may NOT be eligible if...** - Your tumor is growing inside the airway or trachea - You have uncontrolled illness - You are pregnant - You are already participating in another interventional trial - For ultra-central tumors: you have a pacemaker or MRI-incompatible metal implants Talk to your doctor to see if this trial is right for you.