Improvement in cranial neuropathies following stereotactic radiotherapy as primary treatment for skull base meningiomas.

Purpose: Many patients with skull base meningiomas (SBMs) develop cranial neuropathies, though there is a paucity in literature regarding cranial neuropathy improvement following treatment. This is even more profound when isolating for patients who received stereotactic radiotherapy (SRT) as their primary treatment without additional open surgery. Our goal was to investigate the effect of SRT on cranial neuropathies secondary to SBMs and identify predictors of favourable treatment response.

Materials and methods: A single-center retrospective case-control study was performed assessing factors associated with cranial neuropathy improvement in patients with SBMs treated with SRT alone. Patients diagnosed with SBMs, having a cranial neuropathy, and treatment with radiation monotherapy were included. Patients without SBMs or who underwent surgery treatments were excluded. Patients with olfactory and vestibulocochlear neuropathies were ultimately excluded due to sample sizes. Subgroup analysis was performed assessing predictors of improvement for optic, extraocular, and trigeminal neuropathy. Statistical analysis was completed using R version 4.0 (R Foundation for Statistical Computing, Vienna, Austria).

Results: Eighty-five patients met the inclusion criteria of SBMs treated with SRT alone. Forty-five patients (52.9%) had improvement in their symptoms. Among the entire cohort, there was no significant difference between gender, age, tumour location, type of neuropathy, duration of symptoms, tumour volume, total radiation dose, or follow-up duration between those who did and those who did not improve. Subgroup analysis demonstrated significant improvement with younger age at diagnosis of optic neuropathy (50.7 vs 59.6 years, p = 0.04), shorter duration of symptoms prior to radiation in those with extraocular neuropathy (3.0 vs 11.5 months, p = 0.02), and lower radiation dose in those with trigeminal neuropathy (50.0 vs 54.0 Gy, p = 0.01).

Conclusions: This study demonstrates that SRT alone resulted in cranial neuropathy improvement in more than half of patients with SBM and identifies factors predictive of symptom resolution.