Comparative Outcomes of Stereotactic Radiosurgery and Surgical Resection for Radiation-Induced Meningiomas

BACKGROUND AND OBJECTIVES: Radiation-induced meningiomas (RIMs) are the most common secondary intracranial tumors. Compared with sporadic meningiomas (SMs), RIMs exhibit more aggressive clinical behavior. Surgical resection has traditionally been the primary treatment modality for these tumors; however, previous studies have demonstrated stereotactic radiosurgery (SRS) is an effective treatment for RIMs. The aims of this study were to further characterize these rare tumors and to directly compare the outcomes after SRS vs surgical resection as the primary treatment modality for RIMs. METHODS: A single-institution retrospective analysis of surgically and SRS-treated RIMs was conducted. Patient demographic data, World Health Organization grade, tumor volume, multiplicity, complications, and extent of resection were collected. The primary outcome was local control. RESULTS: Forty-seven patients with one or multiple RIMs comprising 73 tumors were identified and compared with a cohort of 75 patients with SMs (n = 86 tumors). Patients with RIMs more frequently harbored multiple tumors (44.4% vs 16.0%; P = .002). RIMs treated surgically exhibited a significantly worse local control compared with surgically treated SMs (log-rank P = .043). Among RIMs, primary treatment with SRS was associated with a significantly better local control compared with surgery as the primary treatment modality ( P = .011). SRS demonstrated superior 5- and 7-year local control rates even after controlling for size and restricting the analysis to gross totally resected tumors. CONCLUSION: SRS was associated with better local control compared with surgical resection for the primary treatment of RIMs. Frequent multifocal presentation and high rates of treatment failure support the notion that RIMs represent a distinct biological entity. Given the long latency and ongoing risk of tumor development after cranial irradiation, these findings underscore the importance of long-term surveillance in this patient population.