To define the rate of tumor control and factors associated with radiation-related complications after single-fraction radiosurgery (SRS) for patients with imaging defined intracranial meningiomas.

Retrospective review of 251 patients (192 women, 59 men) having SRS for imaging-defined intracranial meningiomas between 1990 and 2008. Excluded were patients with radiation-induced tumors, meningiomatosis, or neurofibromatosis. The mean patient age was 58.6 ± 13.4 years. The majority of tumors involved the skull base/tentorium (n = 210, 83.7%). The mean treatment volume was 7.7 ± 6.2 cm(3); the mean tumor margin dose was 15.8 ± 2.0 Gy. Follow-up (mean, 62.9 ± 43.9 months) was censored at last evaluation (n = 224), death (n = 22), or tumor resection (n = 5).

No patient died from tumor progression or radiation-related complications. Tumor size decreased in 181 patients (72.1%) and was unchanged in 67 patients (26.7%). Three patients (1.2%) had in-field tumor progression noted at 28, 145, and 150 months, respectively. No patient had a marginal tumor progression. The 3- and 10-year local control rate was 99.4%. One patient had distant tumor progression at 105 months and underwent repeat SRS. Thirty-one patients (12.4%) had either temporary (n = 8, 3.2%) or permanent (n = 23, 9.2%) symptomatic radiation-related complications including cranial nerve deficits (n = 14), headaches (n = 5), hemiparesis (n = 5), new/worsened seizure (n = 4), cyst-formation (n = 1), hemifacial spasm (n = 1), and stroke (n = 1). The 1- and 5-year complication rates were 8.3% and 11.5%, respectively. Radiation-related complications were associated with convexity/falx tumors (HR = 2.8, 95% CI 1.3-6.1, p = 0.009) and increasing tumor volume (HR = 1.05, 95% CI 1.0-1.1, p = 0.04) on multivariate analysis. No patient developed a radiation-induced tumor.

Single-fraction SRS at the used dose range provides a high rate of tumor control for patients with imaging defined intracranial meningiomas. However, treatment failures were noted after 10 years emphasizing the need for long-term imaging follow-up after meningioma SRS.