Stereotactic Radiosurgery in Large Intracranial Meningiomas: A Systematic Review

Gross total resection of large intracranial meningiomas (LIMs) can be challenging and cause significant morbidity and mortality. The aim of this systematic review is to determine the clinical effectiveness and safety of stereotactic radiosurgery (SRS) either as primary or adjuvant therapy for LIMs with tumors >= 2.5 cm in maximum dimension (tumor volume >= 8.1 cm(3)). A total of 452 tumors in 496 patients (350 female [69.3%] and 146 male [30.6%]) with median age 60 years (48-65 years) were included. The median tumor volume at the time of diagnosis was 16.7 cm(3) (10-53.3 cm(3)). The tumors typically were located in the skull base (77.2%), whereas only 14.6% were in the supratentorial space. The median follow-up after SRS was 54 months (18-90 months). In total, 87.8% of patients were treated with single-session (SS) Gamma Knife radiosurgery (GKS), whereas the remaining 12.1% patients received non-SS GKS. Of 452 LIMs assessed for clinical response, 45.1% showed improvement and 15.7% deteriorated after SRS. Radiographic tumor control at last follow-up (2-7.5 years) ranged from 84% to 100%. Overall, radiation-induced toxicity occurred in 23% of patients, with the most common adverse effect being cranial nerve neuropathy (5.5%) and peritumoral edema (5.3%). Subgroup analysis revealed that there is 2-fold greater likelihood of improvement in clinical symptoms in patients with non-SS GKS than SS GKS (odds ratio 2.47; 95% confidence interval 1.38-4.44; P = 0.002). SRS is safe and effective in the treatment of LIMs as primary or adjuvant treatment. Further prospective studies are required to validate our results.