Stereotactic radiosurgery for deep-seated cavernous malformations: a move toward more active, early intervention

Abstract

Object The role of radiosurgery in the treatment of cavernous malformations (CMs) remains controversial. It is frequently recommended only for inoperable lesions that have bled at least twice. Rehemorrhage can carry a substantial risk of morbidity, however. The authors reviewed their practice of treating deep-seated inoperable CMs to assess the complication rate of radiosurgery, the impact that radiosurgery might have on rebleeding, and whether a more active, earlier intervention is justified in managing this condition. Methods The authors performed a retrospective analysis of 113 patients with 79 brainstem and 39 thalamic/basal ganglia CMs treated with Gamma Knife surgery. Lesions were stratified into 2 groups: those that might be lower risk with no more than 1 symptomatic bleed before radiosurgical treatment and those deemed high risk with multiple symptomatic hemorrhages before treatment. Results Forty-one CMs had multiple symptomatic hemorrhages before radiosurgery with a first-ever bleed rate of 2.9% per lesion per year, a rebleed rate of 30.5% per lesion per year, and a median time of 1.5 years between the first and second bleeds. In this group the rebleed rate decreased to 15% for the first 2 years after radiosurgery and declined further to 2.4% thereafter. Pretreatment multiple bleeds led to persistent deficits in 72% of the patients. Seventy-seven CMs had no more than 1 symptomatic bleed before radiosurgery, making for a lifetime bleed rate of 2.2% per lesion per year. The short period between the presenting bleed and treatment (median 1 year) makes the natural history in this group uncertain. The rate of hemorrhage in the first 2 years after treatment was 5.1%, and 1.3% thereafter. Pretreatment hemorrhages resulted in permanent deficits in 43% of the patients in this group, a rate significantly lower than in the multiple-bleeds group (p < 0.001). Posttreatment hemorrhages led to persistent deficits in only 7.3% of the patients. Permanent adverse radiation effects were rare (7.3%) and minor in both groups. Conclusions Stereotactic radiosurgery is a safe management strategy for CMs in eloquent sites with the marked advantage of reducing rebleed risks in patients with repeated pretreatment hemorrhages. The benefit in treating CMs with a single bleed is less clear. Note, however, that repeated hemorrhage carries a significant risk of increased morbidity far in excess of any radiosurgery-related morbidity, and the authors assert that this finding justifies the early active management of deep-seated CMs.

Significant Hemorrhage Rate Reduction after Gamma Knife Radiosurgery in Symptomatic Cavernous Malformations: Long-Term Outcome in 95 Case Series and Literature Review

“…In the case of CMs, different latency periods have been chosen in the literature, from 2 to 4 years [2,5,10,14,15,16,17,18,19]. There is no way of confirming thrombo-obliteration response by imaging studies, although it is possible to evidence a decrease in volume with MRI in many cases.…”

“…In our study we presumed that the lesions were present from birth [2,13,20]. The bleeding risk could be underestimated, but our intention was to avoid overestimation of the pretreatment hemorrhage rate in order to further validate SRS posttreatment results.…”

“…CMs located in highly eloquent areas seem to be more aggressive than superficial lesions. This may be the reason that bleeding is more likely to be symptomatic in these locations [2,3,4]. Bleeding risk seems to increase during the first months after a bleeding episode to 34% per patient-year [5].…”

Surgical approaches to brainstem cavernous malformations

“…2,9,12 We believe that this treatment requires further validation. Our preference has not been to recommend radiation treatment for brainstem CMs.…”

Editorial

“…Nagy and coauthors 8 have put forth a reasonable argument for radiosurgery in patients with deep-seated (brainstem, thalamus, or basal ganglia) CMs and in those who have had at least 1 symptomatic hemorrhage. There is little doubt of the substantial morbidity associated with a "symptomatic" hemorrhage (defined in their study as a "sudden neurological event associated with a radiologically identifiable bleed") in patients.…”