Radiation-induced meningiomas: A systematic review and meta-analysis of 927 meningiomas

Meningiomas are the most common intracranial tumor. Ionizing radiation has been implicated in the pathogenesis of radiation-induced meningiomas (RIM). Compared to spontaneous meningiomas, RIM are a clinically aggressive entity and are more likely to develop clinical and radiologic progression.

Systematic searches of Medline, Embase, and Cochrane Central Register of Controlled Trials were performed. Pooled data were used to calculate rates of survival, tumor control, and adverse events.

Thirty studies met the final inclusion criterion within this meta-analysis. In total, these studies reported on 927 RIMs in 825 patients. Patients were grouped by whether they received cranial radiotherapy ([CRT]; n = 555 patients) or scalp radiotherapy for tinea capitis ([TC]; n = 270 patients). The median dose prescribed to the CRT and TC groups was ~30 Gy and 1.5 Gy, respectively. The radiation interval to meningioma development between CRT and TC groups were 21.54 and 40.49 years, respectively (P < 0.0001). Twenty-six studies reported a 1-year overall survival rate, with a pooled survival rate of 95.46% (95% confidence interval [CI]: 92.31-97.82%, I2 = 51.9%, P = 0.0012). One-year progression-free survival was reported by 9 studies, with a pooled rate of 99.71% (95% CI: 97.62-100.00%, I² = 3.3%, P = 0.4076). From two studies, the pooled 1-year local recurrence rate was 16.54% (95% CI: 0.00-34.06%, I² = 0.0%, P = 0.5918), while the overall pooled local recurrence rate was 27.35% (95% CI: 17.98-36.73%, I² = 74.5%, P < 0.0001) from 23 studies.

High- and low-dose cranial radiation therapy can differentially influence the latency and grade of RIM, with higher dose CRT associated with earlier onset and more atypical tumors RIM screening may be warranted in individuals with an early exposure to cranial radiation given the increased risk of developing secondary neoplasms. These findings support structured long-term magnetic resonance imaging surveillance for survivors of childhood cranial irradiation, with risk adapted follow-up protocols to enable earlier detection and management.