Radiotherapy is a cancer treatment modality used for local tumor control; it can be used alone or in combination with other modalities (surgery or chemotherapy) for better tumor control. Because radiation therapy is most effective when used in small tumors or microscopic disease, surgery is recommended as a primary treatment, when feasible, and radiation is used for control of residual disease.

Depending on the tumor type, characteristics, and extension of disease, two types of radiation modalities are used: one with definitive intention or long-term control (curative radiation), and one as a palliative treatment. Palliative radiation therapy is mainly used for pain relief and improvement of function of the affected site. Radiation protocols vary in dose and duration time (4 to 20 treatments), and they have to be administered while the patient is under general anesthesia.

For more information, see Radiation Oncology.