Local Control of Low-Volume Brain Metastasis Using Stereotactic Radiosurgery

Abstract

Stereotactic radiosurgery (SRS) is a non-invasive means of treating brain metastases with high dose radiation therapy in a single fraction. It is a useful alternative to surgical resection in selected patients with good performance status and low-volume brain metastases. It can complement or replace whole brain radiation therapy (WBRT), which has historically been the mainstay of palliative brain radiation therapy. Randomized clinical trials have demonstrated the survival benefit of adding SRS to WBRT in the case of a single brain metastasis in a patient with good performance status. Conversely, there appears to be no survival detriment to using SRS alone in patients with up to 4 and possibly even more brain metastases. While there is an increase in recurrent lesions either locally or in distant areas of the brain with the use of SRS alone, these are amenable to salvage therapy if found early with stringent follow-up imaging. Such a strategy has been used successfully in our institution and others to delay or forego WBRT in most patients with low-volume brain metastases. This helps to avoid the morbidities that have been documented with WBRT including neurocognitive impairment, alopecia, fatigue and associated psychological stress. In addition, SRS alone avoids the delay in systemic therapy that is common with the use of WBRT. In this chapter, we focus on the randomized clinical trials that have examined SRS as a primary treatment modality for low-volume brain metastases.