Primary Tumor Resection for M1a Stage Lung Cancer

This study is looking at whether surgically removing the primary (original) lung tumor in patients whose lung cancer has spread to the lining around the lung (called M1a stage) leads to better outcomes. In M1a lung cancer, tiny cancer cells are found on the pleura (the thin tissue lining the lungs) — and it is currently unclear whether removing the main tumor still helps patients. This trial aims to answer that question. **You may be eligible if...** - You are between 18 and 80 years old - You have been diagnosed with M1a stage lung cancer (cancer found on the pleural lining during or after surgery) - This is your first time receiving treatment for lung cancer — no prior surgery, chemotherapy, or radiation - Your lymph nodes were staged as cN0 before surgery (no apparent lymph node spread) - You are in good physical condition (ECOG score 0 or 1) **You may NOT be eligible if...** - The tumor cannot be fully removed surgically - You have a different type of lung malignancy (not lung cancer) - You have already had lung cancer surgery - You have already received radiation or chemotherapy for this cancer Talk to your doctor to see if this trial is right for you.