Proton Beam Radiation Therapy After Treatment for Resected N2 Non-Small Cell Lung Cancer

This clinical trial tests proton beam radiation therapy in patients with non-small cell lung cancer who have undergone surgical resection and have lymph nodes involving the middle of the chest. Proton therapy is a type of radiation treatment that kills cancer cells while avoiding surrounding healthy tissue. Proton beam therapy is sometimes used after cancer surgery to reduce the risk of cancer recurrence (coming back). Giving proton beam radiation therapy may work better than conventional radiation treatment after surgery in patients with non-small cell lung cancer.