Perilesional Edema as a Predictor of Local Failure in Metastatic Brain Lesions Treated With Stereotactic Radiosurgery: A Systematic Review and Meta-Analysis.

Abstract

Identifying prognostic factors to improve local tumor control (LTC) after stereotactic radiosurgery (SRS) for brain metastases (BM) is crucial for optimizing patient outcomes. This study synthesizes evidence on the impact of perilesional edema (PLE) on LTC in BM managed with SRS. A systematic search was conducted in PubMed, Scopus, Embase, and Web of Science, to identify relevant studies reporting PLE as a prognostic factor for LTC in BM treated with SRS. Nine studies, comprising 829 patients treated for 1742 BM treated with SRS, met the inclusion criteria. For the primary analysis, 8 studies involving 1455 BM were included. A random-effects model demonstrated that higher or present PLE was associated with an increased risk of local failure (hazard ratio [HR] = 1.82; 95% CI, 1.42-2.34; I² = 13.8%). Subgroup analyses using a fixed-effect model revealed further insights: studies defining PLE using numeric cutoffs showed a higher risk of local failure (HR = 1.71; 95% CI, 1.39-2.10; I² = 0%), whereas studies dichotomizing PLE as present versus absent observed an even greater risk (HR = 2.78; 95% CI, 1.65-4.69; I² = 33.5%). Sensitivity analysis incorporating all 9 studies confirmed a significant association between PLE and local failure but introduced notable heterogeneity (HR = 1.68; 95% CI, 1.17-2.43; I² = 81.3%). Pretreatment PLE in BM is associated with an increased risk of local failure following SRS, with local failure rates more than doubling in lesions exhibiting edema at the time of treatment. Future research should explore the potential of edema-reducing therapies administered at the time of SRS to improve treatment outcomes.