Long-term control of petroclival meningiomas through radiosurgery

Abstract

Object Because of their critical location adjacent to brain, cranial nerve, and vascular structures, petroclival meningiomas remain a clinical challenge. The authors evaluated outcomes in 168 patients with petroclival meningiomas who underwent Gamma Knife surgery (GKS) during a 21-year interval. Methods Gamma Knife surgery was used as either primary or adjuvant treatment of 168 petroclival meningiomas involving the region between the petrous apex and the upper two-thirds of the clivus. The most common presenting symptoms were trigeminal nerve dysfunction, balance problems, diplopia, and hearing loss. The median tumor volume was 6.1 cm3 (range 0.3–32.5 cm3), and the median radiation dose to the tumor margin was 13 Gy (range 9–18 Gy). Results During a median follow-up of 72 months, neurological status improved in 44 patients (26%), remained stable in 98 (58%), and worsened in 26 (15%). Tumor volume decreased in 78 patients (46%), remained stable in 74 (44%), and increased in 16 (10%), all of whom were subjected to additional management strategies. Overall 5- and 10-year progression-free survival rates were 91 and 86%, respectively. Patients followed up for at least 10 years (31 patients) had tumor and symptom control rates of 97 and 94%, respectively. Eight patients had repeat radiosurgery, 4 underwent delayed resection, and 4 had fractionated radiation therapy. Cerebrospinal fluid diversion was performed in 7 patients (4%). Significant risk factors for tumor progression were a tumor volume ≥ 8 cm3 (p = 0.001) and male sex (p = 0.02). Conclusions In this 21-year experience, GKS for petroclival meningiomas obviated initial or further resection in 98% of patients and was associated with a low risk of adverse radiation effects. The authors believe that radiosurgery should be considered as an initial option for patients with smaller-volume, symptomatic petroclival meningiomas.