Tumor Control and Cranial Nerve Outcomes After Adjuvant Radiosurgery for Low-Grade Skull Base Meningiomas

We evaluated the tumor control and cranial nerve (CN) outcomes after adjuvant stereotactic radiosurgery (SRS) for petroclival, cavernous sinus, and cerebellopontine angle meningiomas.

From our prospectively maintained database of 2022 patients with meningioma who had undergone Leksell SRS during a 30-year interval, we found 43 patients with petroclival, 94 with cavernous sinus, and 13 patients with cerebellopontine angle meningiomas who had undergone adjuvant SRS after surgical resection of the meningioma. The patients included in the present report had had ≥1 CN deficit at the initial presentation and a minimum follow-up period of 12 months. The median age at SRS was 54 years (range, 22-81). SRS was performed for residual tumor in 104 patients (69%) and recurrent tumor in 46 patients (31%). The median tumor volume treated with SRS was 8.1 cm³ (range, 0.3-42), and the median margin dose was 13 Gy (range, 10-20).

Tumor control was achieved in 135 patients (90%) at a median follow-up point of 75 months. The progression-free survival rate after SRS was 99.5% at 1 year, 98% at 3 years, 95% at 5 years, and 90% at 10 years. Overall, 29 of the 150 patients (19%) reported improvement in CN function. Deterioration in CN function after SRS developed in 15 patients (10%). The rate of deterioration was 3.5% at 1 year, 5.5% at 3 years, and 7% at 5 years.

Adjuvant SRS provides effective tumor control and a low rate of new or worsening CN deficits.