Recovery of cranial nerve neuropathies after LINAC-based stereotactic radiosurgery for benign cavernous sinus meningioma.

Abstract

Cranial Nerve Neuropathies (CNNs) often accompany Cavernous Sinus Meningioma (CSM), for which Stereotactic Radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSR) are established treatments. This study assesses CNNs recovery in CSM patients treated with LINAC, offering insight into treatment effectiveness. This study was conducted on 128patients with CSM treated with LINAC-based SRS/FSR between 2005 and 2020 at a single institution. 46 patients presented with CNNs. The study analyzed patients' demographics, clinical parameters, SRS/FSR treatment characteristics, post-treatment CNNs recovery duration, status, and radiological control on their last follow-up. The median follow-up duration was 53.4months. Patients were treated with SRS (n = 25) or FSR (n = 21). The mean pretreatment tumor volume was 9.5cc decreasing to a mean end-of-follow-up tumor volume was 5.1cc. Radiological tumor control was achieved in all cases. CNN recovery was observed in 80.4% of patients, with specific nerve recoveries documented as follows: extra-ocular nerves (43.2%), trigeminal nerve (32.4%), and optic nerve (10.8%). A higher CNNs recovery rate was associated with a smaller pre-treatment tumor volume (p < 0.001), and the median time-to-improvement was 3.7months. Patients with tumor volumes exceeding 6.8cc and those treated with FSR exhibited prolonged time-to-improvement (P < 0.03 and P < 0.04 respectively). This study suggests that SRS/FSR for CSM provides good and sustainable CNNs recovery outcomes with excellent long-term radiological control. A higher CNNs recovery rate was associated with a smaller pre-treatment tumor volume. while shorter time-to-improvement was identified in patients treated with SRS compared to FSR, particularly in those with small pre-treatment tumor volume.