Radiation therapy is used to treat lung tumors painlessly and noninvasively. During treatment, radiation passes through the chest to destroy the cancer cells in lung tumors, Radiation therapy may be combined with surgery, chemotherapy or both depending on the circumstances. Side effects are usually minimal, and most patients return to their normal activities following each treatment. Radiation therapy serves as an effective lung cancer treatment, working within cancer cells to damage their ability to multiply. Several factors determine candidacy for radiation therapy treatment including the type and stage of your lung cancer, as well as your overall health.