Intracranial meningiomas may be induced after radiation exposure, for example radiotherapy of CNS malignancies. However, little data is available regarding their nature and characteristics of affected patients.

This study aimed to evaluate clinical features and potential differences in surgical treatment of radiation induced meningiomas.

A single-center retrospective study including patients undergoing resection of intracranial meningiomas between 2007 and 2018 was performed. Patients with intracranial radiation exposure were identified using hospital records and compared with non-radiation induced cases.

During this period, 841 meningioma patients with sufficient medical records were identified. Radiation-induced meningiomas were present in 33 (3.9%) cases.

Median age at diagnosis was 60 (50-70) years. Patients being exposed to radiotherapy prior to development of meningiomas were younger (49.3±14.4 vs 59.8±13.3 years, p<0.001) and presented with smaller tumor diameter (31.9±18.2 vs 32.9±17.1mm p<0.001). The proportion of higher-grade tumor was larger (p=0.001): WHO grade 1 tumors were present in 82.8%, grade 2 in 16.34% and grade 3 in 0.85% of cases. Simpson grade 1 resection was achieved in 38.9%, 2 in 31.3%, 3 in 16.2%, 4 in 13.5%. and 5 in 0.1% of cases. There were no differences in Simpson grade (X2= 1.2 p=0.9) or comorbidities (CCI 2.5±1.6 vs 2.2±1.8 p=0.5).

Location differed significantly favoring more surgically complex regions in radiation-exposed patients (i.e. olfactory groove, cavernous sinus, tuberculum sellae p<0.001). Resection of radiation induced meningiomas subsequently required more manipulation of large intracranial vessels (60% vs 37% p<0.001), but manipulation of cranial nerves was less frequently necessary (30% vs 36% p<0.001).

The management of radiation-induced meningiomas poses additional challenges due to younger patient population, larger proportion of higher-grade tumors and more demanding location.