2078 - Comparative Outcomes of Preoperative vs. Postoperative Stereotactic Radiosurgery for Resected Brain Metastases: A Meta-Analysis (COPPER-BrM)
Presenter(s)
A. G. Gouveia1,2, G. Pond3, K. Dong2, V. F. Bratti4, J. Tao2, G. A. Viani5, G. N. Marta6, S. A. Hanna6, A. Y. Ye7, A. A. Rosa8, D. M. Palhares9, F. L. Cury10, C. A. Beers11, C. J. Villafuerte12, T. Tsakiridis13, R. A. Olson7, and F. Y. Y. Moraes14; 1McMaster University, Juravinski Cancer Center, Hamilton, ON, Canada, 2The University of British Columbia, Vancouver, BC, Canada, 3Escarpment Cancer Research Institute McMaster University, Hamilton, ON, Canada, 4Department of Public Health Sciences, Queen's University, Kingston, ON, Canada, 5Hospital das Clínicas of the São Paulo State University (UNESP), Medical School, Botucatu., Botucatu, SP, Brazil, 6Department of Radiation Oncology, Hospital Sírio-Libanês, Sao Paulo, Brazil, 7University of British Columbia, Vancouver, BC, Canada, 8Hospital Santa Izabel, Salvador, Brazil, 9McMaster University, Hamilton, ON, Canada, 10McGill University Health Centre, Montreal, QC, Canada, 11McMaster University, Department of Oncology, Hamilton, ON, Canada, 12Ateneo School of Medicine and Public Health, Manilla, Philippines, 13Juravinski Cancer Centre, McMaster University, Hamilton, ON, Canada, 14Queen's University, Kingston, ON, Canada
Purpose/Objective(s): The optimal timing of stereotactic radiosurgery (SRS) for resectable brain metastases remains unclear. Patients with brain metastases often receive stereotactic radiosurgery (SRS) following surgical resection to reduce the risk of local recurrence based on current guidelines. However, preoperative SRS may enable more precise target delineation and decrease the risk of leptomeningeal dissemination (LMD), among other complications. This meta-analysis compares oncologic and toxicity outcomes between pre- and postoperative SRS.
Materials/Methods: We conducted a PRISMA/MOOSE-compliant systematic review and meta-analysis of comparative studies of resectable brain metastases treated with pre- or postoperative SRS. Random-effects models were used to generate forest plots of pooled risk ratios (RR) with 95% confidence intervals (CI). Prespecified outcomes included local relapse and overall mortality at 1 and 2 years, as well as radionecrosis (RN) and LMD rates. Statistical analyses were performed using Stata v19.5, with p-values < 0.05 considered statistically significant.
Results: Five studies (n=861) met the inclusion criteria. Local relapse did not differ between strategies at 1 year (RR = 0.96, 95% CI 0.65–1.42) or 2 years (RR = 1.05, 95% CI 0.70–1.57; both I² = 0%). Overall mortality rates at 1 year (RR = 0.99, 95% CI 0.81–1.20; I² = 5.1%) and 2 years (RR = 0.97, 95% CI 0.83–1.12; I² = 0%) were also comparable. Radionecrosis favored the preoperative approach but was not statistically significant (RR = 0.72, 95% CI 0.37–1.37; I² = 42.0%). Preoperative SRS was associated with a significantly lower risk of LMD (RR = 0.44, 95% CI 0.25–0.78; I² = 0.4%), corresponding to a 56% relative risk reduction.
Conclusion: Preoperative SRS provides local control and survival equivalent to postoperative SRS and is associated with a significantly lower risk of LMD. Confirmation in prospective randomized trials is needed to establish causality and refine clinical selection criteria. Other factors that may impact outcomes, such as lesion or resection cavity size, tumor histology, extracranial disease status, and SRS dose and fractionation, should also be considered in future study designs.