Single-fraction radiosurgery of benign intracranial meningiomas

BACKGROUND:: Stereotactic radiosurgery (SRS) of benign intracranial meningiomas is an accepted management option for well-selected patients. OBJECTIVE:: To analyze patients who had single-fraction SRS for benign intracranial meningiomas to determine factors associated with tumor control and neurologic complications. METHODS:: Retrospective review was performed of 416 patients (304 women/112 men) who had single-fraction SRS for imaging defined (n = 252) or confirmed World Health Organization grade I (n = 164) meningiomas from 1990 to 2008. Excluded were patients with radiation-induced tumors, multiple meningiomas, neurofibromatosis type 2, and previous or concurrent radiotherapy. The majority of tumors (n = 337; 81%) involved the cranial base or tentorium. The median tumor volume was 7.3 cm; the median tumor margin dose was 16 Gy. The median follow-up was 60 months. RESULTS:: The disease-specific survival rate was 97% at 5 years and 94% at 10 years. The 5- and 10-year local tumor control rate was 96% and 89%, respectively. Male sex (hazard ratio [HR]: 2.5, P = .03), previous surgery (HR: 6.9, P = .002) and patients with tumors located in the parasagittal/falx/convexity regions (HR: 2.8, P = .02) were negative risk factors for local tumor control. In 45 patients (11%) permanent radiation-related complications developed at a median of 9 months after SRS. The 1- and 5-year radiation-related complication rate was 6% and 11%, respectively. Risk factors for permanent radiation-related complication rate were increasing tumor volume (HR: 1.05, P = .008) and patients with tumors of the parasagittal/falx/convexity regions (HR: 3.0, P = .005). CONCLUSION:: Single-fraction SRS at the studied dose range provided a high rate of tumor control for patients with benign intracranial meningiomas. Patients with small volume, nonoperated cranial base or tentorial meningiomas had the best outcomes after single-fraction SRS.