Tumor control and cranial nerve outcomes after Gamma Knife radiosurgery for Glomus jugulare tumors: a systematic review, meta-analysis, and institutional failure pattern analysis

Purpose To define tumor control, cranial nerve toxicity, and progression patterns after Gamma Knife radiosurgery (GKRS) for glomus jugulare tumors using a systematic review/meta-analysis and an institutional cohort. Methods and Materials A PRISMA-compliant systematic review identified studies reporting outcomes of GKRS for glomus jugulare tumors. Random-effects meta-analyses of proportions were performed for radiographic tumor control, tumor shrinkage, new or worsened cranial nerve deficits, and hearing worsening using endpoint-specific denominators. Heterogeneity was quantified with I 2 . Sensitivity analyses excluding the institutional cohort were performed. The institutional jugulare subset contributed to pooled estimates, whereas the full institutional jugulotympanic cohort was analyzed descriptively for progression-free survival, failure pattern, and salvage. Results Twenty-six cohorts were included. Across 590 tumors, pooled radiographic tumor control after GKRS was 0.91 (95% CI, 0.88–0.94; I 2 = 0.0%). Across 518 tumors, pooled radiographic shrinkage was 0.51 (95% CI, 0.43–0.59; I 2 = 58.4%). Across 463 patients, pooled new or worsened cranial nerve deficit was 0.11 (95% CI, 0.08–0.14; I 2 = 0.0%). Hearing worsening was reported in a limited subset of 114 evaluable patients, with a pooled proportion of 0.16 (95% CI, 0.10–0.24; I 2 = 0.0%). Sensitivity analyses excluding the institutional cohort did not materially change pooled estimates. In the institutional cohort (n = 27), radiographic control at last follow-up was 85.2%. Kaplan–Meier PFS was 100.0% at 24 months and 77.8% at 60 months. Among 4 progression events, failures were predominantly marginal or out-of-field, with no clearly in-field failures; salvage GKRS was feasible in most recurrent cases. Conclusions GKRS provides durable tumor control with a favorable cranial nerve toxicity profile in glomus jugulare tumors. Treatment response is characterized more by stability than regression. In the institutional cohort, progression events were marginal or out-of-field rather than clearly in-field, supporting GKRS as an effective local-control strategy within the treated target while highlighting the importance of careful target delineation and long-term surveillance.