Stereotactic radiosurgery for cerebellopontine angle meningiomas

Abstract

Object To assess the long-term outcomes of stereotactic radiosurgery (SRS) for cerebellopontine angle (CPA) meningiomas, the authors retrospectively reviewed data from a 20-year experience. They evaluated progression-free survival as well as improvement, stabilization, or deterioration in clinical symptoms. Methods Seventy-four patients with CPA meningiomas underwent SRS involving various Gamma Knife technologies between 1990 and 2010. The most common presenting symptoms were dizziness or disequilibrium, hearing loss, facial sensory dysfunction, and headache. The median tumor volume was 3.0 cm3 (range 0.3–17.1 cm3), and the median radiation dose to the tumor margin was 13 Gy (range 11–16 Gy). The median follow-up period was 40 months (range 4–147 months). Results At last imaging follow-up, the tumor volume had decreased in 46 patients (62%), remained stable in 26 patients (35%), and increased in 2 patients (3%). The progression-free survival after SRS was 98% at 1 year, 98% at 3 years, and 95% at 5 years. At the last clinical follow-up, 23 patients (31%) showed neurological improvement, 43 patients (58%) showed no change in symptoms or signs, and 8 patients (11%) had worsening symptoms or signs. The neurological improvement rate after SRS was 16% at 1 year, 31% at 3 years, and 40% at 5 years. The post-SRS deterioration rate was 5% at 1 year, 10% at 3 years, and 16% at 5 years. A multivariate analysis demonstrated that trigeminal neuralgia was the symptom most likely to worsen after SRS (HR 0.08, 95% CI 0.02–0.31; p = 0.001). Asymptomatic peritumoral edema occurred in 4 patients (5%) after SRS, and symptomatic adverse radiation effects developed in 7 patients (9%). Conclusions Stereotactic radiosurgery for CPA meningiomas provided a high tumor control rate and relatively low risk of ARE. Tumor compression of the trigeminal nerve by a CPA meningioma resulted in an increased rate of facial pain worsening in this patient experience.

Efficacy and outcomes of facial nerve–sparing treatment approach to cerebellopontine angle meningiomas

“…13 Involvement of the IAC was noted to occur in 40 (52.6%) patients, similar to that reported in the literature. 1,7,10,13,19 Tumors arising from the anterior and posterior petrous dura were more likely to undergo GTR than tumors arising from the petroclival region or the tentorium (p = 0.041). Petroclival tumors uniformly underwent STR, likely reflecting their deep anterior attachment and the surgeon's efforts to preserve CN VI as it traversed the operative field.…”

Gamma Knife radiosurgery for meningiomas arising from the tentorium: a 22-year experience

“…We did not include cerebellopontine, petroclival meningiomas, or other meningiomas that appeared to arise adjacent to the petrous bone. Radiosurgery was performed in the following patients: those with recurrent or residual tumors after initial microsurgery; those with symptomatic primary tumors in locations associated with a high risk for complete tumor removal; those with medical comorbidities or advanced age; and those younger patients who declined microsurgery or continued observation [17]. The tentorial meningiomas were classified according to the modified scheme proposed by Yasargil [1,18]: medial, falcotentorial, paramedian, peritorcular, or lateral meningioma ( Table 1).…”

When is an acoustic neuroma not an acoustic neuroma? Pitfalls for radiosurgeons

“…Limited retrospective data suggest that non-vestibular schwannomas are appropriately treated with similar marginal doses to AN, 1 and the range of doses reported for CPA meningiomas also typically overlaps with that of AN. 7,8 Instead, the real issue is geographical miss from failure to recognise tumour extension atypical for AN (case 1), and accordingly, particular attention to the regions immediately lateral and inferior to the main tumour mass on MRI is critical.…”