Stereotactic radiosurgery for brain oligometastases: good for some, better for all?

Brain metastasis is the commonest central nervous system neoplasm affecting 25% patients with cancer. Recursive Partitioning Analysis (RPA) is a reliable prognostic index for patients with brain metastases. In patients with oligometastases and good performance status, decision-making regarding stereotactic radiosurgery (SRS) boost, following whole brain radiation therapy (WBRT), is guided by patient preference, access to radiosurgical facility and institutional policy. Published data for this review was identified by a systematic search of MEDLINE, CANCERLIT and EMBASE databases from 1990 until the present date and was restricted to the English language using appropriate search terms. All three identified randomized controlled trials consistently showed that radiosurgery improves intracranial local control (Level I evidence). Survival benefit, however, is limited to a selected subset of patients (RPA class 1) only. More importantly, patients receiving SRS have significantly better performance scores and decreased steroid requirements resulting in improved health-related quality-of-life (HRQoL). There is no head-to-head comparison of radiosurgery with neurosurgery in resectable single metastasis. SRS is associated with an improvement in outcome. A trial of radiosurgery versus neurosurgery should be attempted to define better the role of SRS in resectable single metastasis. Formal HRQoL assessments should be incorporated as primary end points in future prospective trials.