Stereotactic body radiotherapy.

Extracranial stereotactic body radiotherapy (SBRT) has been developed and refined over the last 25 years as a means to precisely deliver ablative doses of hypofractionated radiotherapy to small targets located outside of the cranial vault. SBRT has armed the radiation oncologist with a therapeutic approach that allows for intensification of both dose delivered and fractionation regimen employed. As a consequence, tumor control rates have improved to levels that previously have been associated only with surgical resection. Several prospective phase I and II studies have evaluated the use of SBRT for non-small cell lung cancer (NSCLC), liver tumors, and spinal metastases. This article will give an overview of SBRT and evidence for its use in the most common sites of disease for which it is employed today.