LMAP-16 THE EFFECTS OF POSTOPERATIVE STEREOTACTIC RADIOSURGERY TIMING ON CLINICAL OUTCOMES IN PATIENTS WITH INTRACRANIAL METASTASES: A SYSTEMATIC REVIEW AND META-ANALYSIS

Stereotactic radiosurgery (SRS) after neurosurgical resection improves local tumor control in patients with metastatic brain cancer. However, the influence of timing on its therapeutic efficacy is unclear, and a lack of consensus and standardization limits its optimization. We performed a systematic review and meta-analysis examining publications that reported the timing of postoperative SRS for patients with intracranial metastases. Our primary outcomes included median overall survival and rates of local and regional failure, while our secondary outcomes examined the incidence of treatment-related adverse events. Correlations between median SRS timing and these variables were assessed using linear regression and publication bias was appraised via Egger’s test. Our systematic review resulted in 22 articles comprising 1338 patients who met the criteria for inclusion. The median timing of adjuvant SRS spanned 14.5 to 41 days. There was a significant positive study-level correlation of median time to SRS with regional failure (P=0.043, R(2)=0.32) but not with overall survival (P=0.54, R(2)=0.03) or local failure (P=0.16, R(2)= 0.14). Data regarding adverse events related to treatment was limited in the literature and there was significant heterogeneity within the reports (P<0.0001). Overall, our results demonstrate institutions with a longer time between surgery and SRS had lower rates of regional failure, however, this did not affect rates of local failure or patient survival. Further research is warranted to elucidate the role of timing for postoperative SRS on oncologic outcomes as well as the factors that contribute to optimal radiosurgery workflow in this patient population.