Patient selection criteria for the treatment of brain metastases with stereotactic radiosurgery

In this study we evaluate prognostic factors that predict local-regional control and survival following stereotactic radiosurgery (SRS) in patients with brain metastasis and establish guidelines for patient selection. Our evaluation is based on 73 patients with brain metastasis treated with SRS at the University of Minnesota between March 1991 and November 1995. The ability of stereotactic radiosurgery to improve local control in patients with brain metastases is confirmed in our study in which only 6 of 62 patients failed locally after SRS, with an actuarial local progression-free survival of 80% at 2 years. Variables that predicted worse prognosis were larger tumor size (p=0.05) for local progression-free survival and multiplicity of metastasis (p=0.03) and infratentiorial location of metastases (p=0.006) for regional progression-free survival. Absence of extracranial disease, KPS ≥ 70, and single intracranial metastasis were significant predictors of longer survival. Patients who fulfill all three criteria will survive longer after SRS (MS=17.7 months) and will most likely benefit from the increase local control in the brain achieved by SRS. Survival in patients who do not meet any of these criteria is very poor (MS=1.5 months), and these patients are less likely to benefit from this treatment. Careful selection of patients for SRS is warranted.