This document summarizes information about lung cancer types, risk factors, staging, and the role of radiotherapy in treatment. It notes that non-small cell lung cancer (NSCLC) accounts for 80% of cases, with the most common subtypes being adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Smoking is the primary risk factor. Radiotherapy can play definitive, adjuvant, or palliative roles. For early-stage NSCLC, stereotactic body radiotherapy is recommended. For locally advanced NSCLC, concurrent chemoradiotherapy is standard. Post-operative radiotherapy may improve outcomes for patients with pathological N2 disease but not for N0-1 disease.