Long-Term Survivorship Following Stereotactic Radiosurgery Alone for Brain Metastases: Risk of Intracranial Failure and Implications for Surveillance and Counseling

Abstract

Background Historically, survival for even highly select cohorts of brain metastasis patients selected for SRS alone is Objective To investigate the possibility that for subsets of patients the risk of intracranial failure beyond 2 yr is less than the commonly quoted 50% to 60%, wherein less frequent screening may be appropriate. Methods As a part of our institutional radiosurgery database, we identified 132 patients treated initially with stereotactic radiosurgery (SRS) alone (± pre-SRS surgical resection) with at least 2 yr of survival and follow-up from SRS. Primary study endpoints were rates of actuarial intracranial progression beyond 2 yr, calculated using the Kaplan-Meier and Cox regression methods. Results The median follow-up from the first course of SRS was 3.5 yr. Significant predictors of intracranial failure beyond 2 yr included intracranial failure before 2 yr (52% vs 25%, P Conclusion Relapse rates beyond 2 yr following SRS alone for brain metastases are low in patients who do not suffer intracranial relapse within the first 2 yr and with low-volume brain metastases, supporting a practice of less frequent screening beyond 2 yr. For remaining patients, frequent (every 3-4 mo) screening remains prudent, as the risk of intracranial failure after 2 yr remains high.