Defining Long-Term Clinical Outcomes and Risks of Stereotactic Radiosurgery for Brainstem Cavernous Malformations

Stereotactic radiosurgery for haemorrhagic cerebral cavernous malformation: a multi-institutional, retrospective study

BACKGROUND

Cerebral cavernous malformations (CCMs) frequently manifest with haemorrhages. Stereotactic radiosurgery (SRS) has been employed for CCM not suitable for resection. Its effect on reducing haemorrhage risk is still controversial. The aim of this study was to expand on the safety and efficacy of SRS for haemorrhagic CCM.

METHODS

This retrospective multicentric study included CCM with at least one haemorrhage treated with single-session SRS. The annual haemorrhagic rate (AHR) was calculated before and after SRS. Recurrent event analysis and Cox regression were used to evaluate factors associated with haemorrhage. Adverse radiation effects (AREs) and occurrence of new neurological deficits were recorded.

RESULTS

The study included 381 patients (median age: 37.5 years (Q1-Q3: 25.8-51.9) with 414 CCMs. The AHR from diagnosis to SRS excluding the first haemorrhage was 11.08 per 100 CCM-years and was reduced to 2.7 per 100 CCM-years after treatment. In recurrent event analysis, SRS, HR 0.27 (95% CI 0.17 to 0.44), p<0.0001 was associated with a decreased risk of haemorrhage, and the presence of developmental venous anomaly (DVA) with an increased risk, HR 1.60 (95% CI 1.07 to 2.40), p=0.022. The cumulative risk of first haemorrhage after SRS was 9.4% (95% CI 6% to 12.6%) at 5 years and 15.6% (95% CI% 9 to 21.8%) at 10 years. Margin doses> 13 Gy, HR 2.27 (95% CI 1.20 to 4.32), p=0.012 and the presence of DVA, HR 2.08 (95% CI 1.00 to 4.31), p=0.049 were factors associated with higher probability of post-SRS haemorrhage. Post-SRS haemorrhage was symptomatic in 22 out of 381 (5.8%) patients, presenting with transient (15/381) or permanent (7/381) neurological deficit. ARE occurred in 11.1% (46/414) CCM and was responsible for transient neurological deficit in 3.9% (15/381) of the patients and permanent deficit in 1.1% (4/381) of the patients. Margin doses >13 Gy and CCM volume >0.7 cc were associated with increased risk of ARE.

CONCLUSION

Single-session SRS for haemorrhagic CCM is associated with a decrease in haemorrhage rate. Margin doses ≤13 Gy seem advisable.

Stereotactic radiosurgery for intracranial cavernous malformations of the deep-seated locations: systematic review and meta-analysis

OBJECTIVE

To determine the outcomes of stereotactic radiosurgery (SRS) for deep-seated (brainstem, basal ganglia, thalamus, cerebellar peduncle) intracranial cavernous malformations (ICMs).

METHODS

A systematic review and meta-analysis was performed according to PRISMA and MOOSE guidelines. The main outcomes were comparing pre- and post-SRS hemorrhage rates, using the pooled risk ratios (RR) as the measure of effect. Additionally, the study assessed lesion volume changes and radiation-injury incidence.

RESULTS

Data of 850 patients across 14 studies were included in the meta-analysis. The pooled RR of all deep-seated ICMs show a decrease in hemorrhage rate after SRS compared to pre-SRS over the total follow-up period (RR =0.13), initial 2 years (RR =0.22), and after 2 years (RR =0.07). For 9 studies that reported hemorrhage rate of the brainstem only, the pooled RR shows a decrease of hemorrhage rate after SRS compared to pre-SRS over the total follow-up period (RR =0.13), initial 2 years (RR =0.19), and after 2 years (RR =0.07). Volumetric regression was achieved in 44.25% and stability in 56.1%. The pooled incidence of symptomatic and permanent radiation injury was 9% (95% CI, 7-11) and 3% (95% CI, 0-1.9%), respectively.

CONCLUSION

SRS appears effective in reducing hemorrhage rates for deep-seated ICMs. The risk of symptomatic radiation injury is low. Given the high risk of surgical morbidity, SRS is a reasonable treatment option for patients with deep-seated ICMs with at least one prior hemorrhage.

[Radiosurgery for cerebral cavernous malformations: a systematic review]

BACKGROUND

Stereotactic radiosurgery (SRS) for cerebral cavernous malformations has been used for more than 30 years. However, indications for this method and outcomes are still discussable.

OBJECTIVE

To analyze available literature data on SRS for cerebral cavernous malformations with assessment of indications for treatment, radiation parameters, radiological and clinical complications and outcomes.

RESULTS

The final analysis included 20 reports describing post-SRS outcomes in 1834 patients with cerebral cavernous malformations. The main radiation parameter was mean radiation dose to the edge of cavernous malformation (prescribed dose, 13.25±2.16 Gy). In natural course of malformation, mean incidence of hemorrhages from cavernous malformation when counted after the second hemorrhage was 25.9±14.6%, after the patient's birth - 2.59±0.44%. Mean follow-up period after SRS was 66.7±24.1 months. Incidence of hemorrhages from cavernous malformation after SRS for the first 2 years of follow-up was assessed in 14 studies (4.67±3.51%). Incidence of hemorrhages ≥2 years after SRS was analyzed in 12 studies (1.55±0.8%).

CONCLUSION

Despite significant global experience in SRS for cerebral cavernous malformations and many studies devoted to this problem, clear patient selection criteria have not yet been formulated. Modern selection principles have insufficient evidence base.

Prognostic Factors Analysis for Intracranial Cavernous Malformations Treated with Linear Accelerator Stereotactic Radiosurgery

Stereotactic radiosurgery (SRS) is generally considered a substitute for cranial cavernous malformations (CCMs). However, prognostic factors for post-radiosurgery CCM rebleeding and adverse radiation effects have not been well evaluated, and the effect of timing and optimal treatment remains controversial. Therefore, this study evaluated prognostic factors for post-radiosurgical rebleeding and focal edematous changes in 30 patients who developed symptomatic intracranial hemorrhage due to solitary non-brainstem CCM and received linear accelerator (LINAC) SRS in a single medical center from October 2002 to June 2018. An overall post-radiosurgical annual hemorrhage rate with 4.5% was determined in this study. In addition, a higher marginal dose of >1600 centigray and earlier LINAC SRS intervention were correlated with a significantly lower post-radiosurgical annual hemorrhage rate. A lesion size larger than 3 cm3 and a coexisting developmental venous anomaly were significant risk factors for post-radiosurgical focal brain edema but mostly resulted in no symptoms and were temporary. This study demonstrated the efficacy of LINAC SRS in preventing CCM rebleeding and suggests that earlier radiosurgery treatment with a higher dose for non-brainstem symptomatic CCMs be considered.

Stereotactic radiosurgery for cerebral cavernous malformation: comparison of hemorrhage rates before and after stereotactic radiosurgery

OBJECTIVE

Cerebral cavernous malformation (CM) is an angiographically occult vascular pathology. Although microsurgery is the gold standard treatment to control the symptoms of CM, resection carries high risk in some situations, especially eloquent areas. The objective was to evaluate annual hemorrhage rates (AHRs) before and after stereotactic radiosurgery (SRS) treatment of cerebral CM in different locations.

METHODS

A total of 195 patients (119 women and 76 men) with CM treated at the Gazi University Gamma Knife Center between April 2005 and June 2017 were analyzed. The mean ± SD follow-up period was 67.4 ± 31.1 months (range 12 days to 170 months). AHR before SRS, AHR after SRS, morbidity associated with radiation, seizure control rate after SRS, lesion volume, coexistence with developmental venous anomaly, and SRS treatment parameters were analyzed, with evaluation of radiological data and clinical charts performed retrospectively. The seizure control rate was assessed using the Engel outcome scale.

RESULTS

The AHR before SRS was 15.3%. Application of SRS to these patients significantly reduced the AHR rates to 2.6% during the first 2 years after treatment and to 1.4% thereafter. Favorable seizure control (Engel class I and II) after radiosurgery was achieved in 23 patients (88.5%) with epilepsy. Radiation-related temporary complications occurred in 15.4% of patients, and permanent morbidity occurred in 4.6%.

CONCLUSIONS

SRS is a safe and effective treatment modality for reducing the hemorrhage risk of CM. The authors suggest that SRS should be considered for the treatment of patients with CM, high surgical risks, and hemorrhage history, instead of a using a wait-and-see policy.

Presentation and management of nervous system cavernous malformations in children: A systematic review and case report

Cerebral cavernous malformations (CMs) are slow-flow vascular lesions that affect up to 0.5% of the pediatric population. These lesions are at risk for hemorrhage, causing seizures, and leading to neurological deficits. Here, we conduct a literature review and then present a report of a supratentorial CM in a 2-year-old patient with no significant past medical history who presented at our institution with 1 month of eye twitching. We performed a literature search of five databases of all articles published before 2020. Our inclusion criteria included cohort and case series of children with mean age under 12 years. Our search yielded 497 unique articles, of which 16 met our inclusion criteria. In our pooled literature analysis, a total of 558 children were included, 8.3% of which had a positive family history and 15.9% had multiple CMs. About 46.1% of the children had seizures, and 88.4% of those who underwent surgery had a total resection. About 85.1% of those with epilepsy were Engel Class 1 postsurgery. Over a mean follow-up of 4.1 years, 3.4% of patients had additional neurological deficits, including paresis and speech deficits. Our analysis of published literature shows surgical intervention should be considered first-line therapy for patients who are symptomatic from CM, present with seizure, and have surgically accessible lesions. Additional work is needed on outcomes and long-term effects of minimally invasive treatments, including radiosurgery and laser ablation, in pediatric populations.

How I do it: Subtemporal transtentorial approach for cavernous malformation of the pons

BACKGROUND

Removal of a pontine cavernous malformation requires sufficient exposure since any restriction on surgical freedom may lead to suboptimal visualization of the lesion, injury to the brainstem, and neurological catastrophe.

METHODS

We describe and demonstrate the subtemporal transtentorial approach to a cavernous malformation of the upper pons, with emphasis on adequate surgical exposure while avoiding the need for extensive bone removal of the skull base.

CONCLUSIONS

The meticulous technique is paramount to the successful removal of any brainstem cavernous malformation. Along with the surgical exposure, delicate handling of the malformation is demonstrated in the accompanying operative video.

Natural History, Clinical, and Surgical Management of Cavernous Malformations

We describe Natural history, clinical and surgical management of cavernous malformation of the brain and spinal cord. Decision-making for treatment of cavernous malformations cannot ignore their natural history and risk of bleeding, which is different depending on the location. Surgical morbidity also depends on the position of the lesion. We performed a review of hemorrhage risk and clinical assessment of superficial and deep supratentorial, brainstem and intramedullary cavernous malformations.

Gamma Knife Radiosurgery For Brain Vascular Malformations: Current Evidence And Future Tasks

Gamma Knife radiosurgery (GKRS) has long been used for treating brain vascular malformations, including arteriovenous malformations (AVMs), dural arteriovenous fistulas (DAVFs), and cavernous malformations (CMs). Herein, current evidence and controversies regarding the role of stereotactic radiosurgery for vascular malformations are described. 1) It has already been established that GKRS achieves 70–85% obliteration rates after a 3–5-year latency period for small to medium-sized AVMs. However, late radiation-induced adverse events (RAEs) including cyst formation, encapsulated hematoma, and tumorigenesis have recently been recognized, and the associated risks, clinical courses, and outcomes are under investigation. SRS-based therapeutic strategies for relatively large AVMs, including staged GKRS and a combination of GKRS and embolization, continue to be developed, though their advantages and disadvantages warrant further investigation. The role of GKRS in managing unruptured AVMs remains controversial since a prospective trial showed no benefit of treatment, necessitating further consideration of this issue. 2) Regarding DAVFs, GKRS achieves 41–90% obliteration rates at the second post-GKRS year with a hemorrhage rate below 5%. Debate continues as to whether GKRS might serve as a first-line solo therapeutic modality given its latency period. Although the post-GKRS outcomes are thought to differ among lesion locations, further outcome analyses regarding DAVF locations are required. 3) GKRS is generally accepted as an alternative for small or medium-sized CMs in which surgery is considered to be too risky. The reported hemorrhage rates ranged from 0.5–5% after GKRS. Higher dose treatments (>15 Gy) were performed during the learning curve, while, with the current standard treatment, a dose range of 12–15 Gy is generally selected, and has resulted in acceptable complication rates (< 5%). Nevertheless, further elucidation of long-term outcomes is essential.

Stereotactic Radiosurgery for Brainstem Cavernous Malformations: An Updated Systematic Review and Meta-Analysis

OBJECTIVE

This study was conducted to achieve more conclusive evidence for the efficacy of stereotactic radiosurgery (SRS) for brainstem cavernous malformations (BSCMs).

METHODS

A literature search of PubMed, EMBASE, and Web of Science was performed and studies reporting the outcomes of SRS for BSCMs were included. The primary outcome was the pre-SRS and post-SRS hemorrhage rates; the pooled incidence rate ratio (IRR) with 95% confidence interval was chosen as effect size. Lesion control, symptom change, and radiation-related complications were evaluated.

RESULTS

A total of 576 patients across 14 studies were included in this meta-analysis. The post-SRS hemorrhage rate was significantly decreased compared with the pre-SRS rate (IRR, 0.123; P < 0.001), and the hemorrhage rate 2 years after SRS was significantly lower than that within 2 years after SRS (IRR, 0.317; P < 0.001). Ten among 14 studies have shown that the symptoms were improved or stationary after SRS. Lesion volume was reduced in 47.3% of the patients and was stationary in 49.4% on the last follow-up images. Symptomatic adverse radiation effects (AREs) developed in 7.3% and permanent AREs were observed in 2.2%. In subgroup analysis, studies having mean marginal dose of ≤13 Gy showed statistically significantly lower development of symptomatic AREs than those having mean marginal dose of >13Gy (2.0% vs. 10.8%; P = 0.008).

CONCLUSIONS

SRS using a relatively low marginal dose can be a safe and effective treatment for BSCM. Further prospective studies are necessary to confirm the optimal radiation dose and efficacy of SRS for BSCMs.