Background: This scoping review investigates factors influencing local control in patients with metastatic brain disease undergoing adjuvant stereotactic radiosurgery (SRS) to surgical cavities. Methods: Seven databases (Ovid Medline, PubMed, Web of Science, EMBASE, BIOSIS, Scopus, Global Health, Cochrane) were searched up to August 2, 2021, using terms related to radiosurgery and brain metastasis. A three-level screening identified relevant studies. Data extraction included study type, population, SRS details, and outcomes. Variables recorded were histopathology, resection degree, number of metastases, SRS platform, dose parameters, cavity volume, margin, time to SRS, local control at 12/24 months, overall, and progression-free survival. Significant predictors were noted. Results: From 10,633 articles, 22 studies with 1,749 cavities. Local control at 12 months was 50–100% (median 82%, IQR 73–84.4%). Distant progression at 12 months was 36–64% (median 45.5%, IQR 38–51%) and at 24 months 39–76% (median 53%, IQR 46–55%). Histology, radiation dose, tumor size, extent of resection, treatment timing, tumor depth, and dural/pial attachment impacted local control, whereas primary disease status, surgical corridor coverage, and tumor location did not. Conclusions: Modifiable SRS treatment and patient selection factors need further investigation. This review emphasizes the necessity for consensus and guides future trials and guidelines to enhance metastatic brain disease management outcomes.