Stereotactic LINAC radiosurgery for the treatment of brainstem cavernomas

The management of deep-seated cerebral cavernous malformations (CCMs) is still controversial. Although surgery remains the treatment of choice in patients with recurrent hemorrhage, patients with CCMs located in the brainstem are in many cases not eligible for resection due to high procedure-related morbidity and mortality. We evaluated the long-term outcome of LINAC radiosurgery (LINAC-RS) for the treatment of brainstem CCMs. Between December 1992 and March 2008, 14 patients (6 men, 8 women) harboring brainstem CCMs underwent LINAC-RS. Pretreatment neuroimaging showed no associated developmental venous angiomas (DVAs) in any of our patients. Prior to treatment, all patients suffered at least from one symptomatic hemorrhage (median 1.8, range 1-3). A median follow-up of 7.1 years (range 2.0-16.8 years) could be obtained in 12 patients. We applied a median tumor surface dose of 13.9 Gy (range 11-18 Gy; median tumor volume 1.6 ml, range 0.4-4.3 ml). Following LINAC-RS, neurological outcome improved in 4 (33.3%) and remained unchanged in 8 patients (66.7%). Rebleeding with subsequent transient neurological status deterioration occurred in 4 patients (33.3%), leading to additional surgical resection in 2 patients (16.7%). The corresponding annual hemorrhage rate was 4.8% (4/82.8 patient-years). Adverse radiation effects (ARE, defined by perilesional hyperintensity on T-2-weighted MR images) were revealed in 3 patients (25%), leading to transient neurological deficits in 2 patients (16.7%). There were no procedure-related complications leading to either permanent morbidity or mortality. Our results support the role of LINAC-RS as an efficient and safe treatment to significantly reduce the annual hemorrhage rate in patients suffering from brainstem CCMs not eligible to microsurgery. Compared with radiosurgery for arteriovenous malformations (AVMs), the intervention-related morbidity is higher.