The role of stereotactic radiotherapy in the treatment of oligometastases.

"Oligometastasis" describes a limited number of metastases arising typically from solid tumors whose behavior suggests an "intermediate" malignant state since it may potentially have a more favorable prognosis. Historically, selected patients with oligometastases often underwent surgical resection since anecdotal evidence suggested it could improve progression-free or overall survival. No prospective randomized trial evidence to date supports survival benefits from surgery. Short courses of highly focused, very high dose radiotherapy (stereotactic radiosurgery; stereotactic body radiotherapy) have emerged as a surgical surrogate to manage oligometastates. For solitary brain metastases, randomized study evidence supports stereotactic radiosurgery as part of their management because of overall survival benefits. Modeled after stereotactic radiosurgery, stereotactic body radiotherapy for extracranial metastases is becoming increasingly common given its efficacy and low toxicity, is an active area of clinical research, and is the subject of this review.