# Is there an optimal time to administer postoperative stereotactic radiosurgery in patients with brain metastases? A systematic review of the literature and meta‐analysis

## TL;DR

This study examines whether the timing of postoperative stereotactic radiosurgery affects outcomes in brain metastasis patients.

## Contribution

The study provides a meta-analysis showing that SRS timing correlates with regional failure but not with survival or local failure.

## Key findings

- Timing of SRS correlated negatively with regional failure (p=0.043, R2=0.32).
- No significant correlation was found between SRS timing and overall survival or local failure.
- Significant heterogeneity was observed across studies (p<0.0001).

## Abstract

Postoperative stereotactic radiosurgery improves local tumor control in patients with metastatic brain cancer. However, the influence of timing on its therapeutic efficacy is unclear. In this study, we performed a meta‐analysis and systematic literature review examining publications that reported the timing of postoperative stereotactic radiosurgery (SRS) for patients with intracranial metastases. Our primary outcomes included median overall survival and rates of local and regional failure, while 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 study resulted in 22 articles comprising 1338 patients. The median timing of adjuvant SRS spanned 14.5 to 41 days. There was a significant negative study‐level correlation of median time to SRS with regional failure (p = 0.043, R2 = 0.32) but not with overall survival (p = 0.54, R2 = 0.03) or local failure (p = 0.16, R2 = 0.14). Additionally, there was significant heterogeneity within the reports (p<0.0001). In conclusion, our analysis demonstrated that postoperative SRS timing did not influence local failure rates which may in part be due to significant variability between individual study designs and patient demographics. Further research is warranted to elucidate the role of timing for postoperative SRS on oncologic outcomes.

Postoperative stereotactic radiosurgery improves local tumor control in patients with metastatic brain cancer. However, the influence of timing on its therapeutic efficacy is unclear. In this study, we performed a meta‐analysis and systematic literature review 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 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 study resulted in 22 articles comprising 1338 patients. The median timing of adjuvant SRS spanned 14.5 to 41 days. There was a significant negative study‐level correlation of median time to SRS with regional failure (p=0.043, R2=0.32) but not with overall survival (p=0.54, R2=0.03) or local failure (p=0.16, R2= 0.14). Additionally, there was significant heterogeneity within the reports (p<0.0001). In conclusion, our analysis demonstrated that postoperative SRS timing did not influence local failure rates which may in part be due to significant variability between individual study designs and patient demographics. Further research is warranted to elucidate the role of timing for postoperative SRS on oncologic outcomes.