Stereotactic radiosurgery for pediatric arteriovenous malformations

Stereotactic Radiosurgery Outcomes in Arteriovenous Malformations: A Pediatric-Adult Comparative Meta-Analysis

BACKGROUND

Stereotactic radiosurgery (SRS) is an established treatment for brain arteriovenous malformations (AVMs), but outcomes between pediatric and adult populations are not well compared. We conducted a systematic review and meta-analysis comparing SRS outcomes for pediatric versus adult AVMs.

METHODS

PubMed was searched for studies reporting SRS outcomes for pediatric or adult AVMs up to January 2024. Primary outcome was obliteration rate, with secondary outcomes including post-SRS hemorrhage, symptomatic radiation-induced changes (RICs), and permanent RICs. Pooled estimates were calculated using random effects models.

RESULTS

Analysis included 22 studies with 3469 patients (1316 pediatric, 2153 adult). Pooled obliteration rate was 63% (95% confidence interval: 56%-70%) overall, with no significant difference between pediatric (61%) and adult (67%) cohorts (P = 0.38). Post-SRS hemorrhage rates were similar (5% pediatric, 6% adult, P = 0.60). Symptomatic RICs occurred in 9% (95% confidence interval: 6%-13%) overall, with 10% in both cohorts (P = 0.91). Permanent RIC rates were 4% in pediatric and 3% in adult cohorts (P = 0.43). Cyst formation (0.6%) and radiation-induced tumors (0.2%) were rare. All-cause mortality was significantly lower in the pediatric cohort (2.6% vs. 9.8%, P = 0.003). Hemorrhagic AVM presentation was inversely correlated with symptomatic RICs across both groups.

CONCLUSIONS

SRS is a reasonable treatment option for appropriately selected AVM patients in both pediatric and adult populations, offering comparable obliteration rates and adverse event profiles. The lower mortality in pediatric patients underscores the importance of early intervention in this population given their high cumulative lifetime rupture risks.

Early obliteration of pediatric brain arteriovenous malformations after stereotactic radiosurgery: an international multicenter study

OBJECTIVE

Stereotactic radiosurgery (SRS) is a treatment option for pediatric brain arteriovenous malformations (AVMs), and early obliteration could encourage SRS utilization for a subset of particularly radiosensitive lesions. The objective of this study was to determine predictors of early obliteration after SRS for pediatric AVMs.

METHODS

The authors performed a retrospective review of the International Radiosurgery Research Foundation AVM database. Obliterated pediatric AVMs were sorted into early (obliteration ≤ 24 months after SRS) and late (obliteration > 24 months after SRS) responders. Predictors of early obliteration were identified, and the outcomes of each group were compared.

RESULTS

The overall study cohort was composed of 345 pediatric patients with obliterated AVMs. The early and late obliteration cohorts were made up of 95 (28%) and 250 (72%) patients, respectively. Independent predictors of early obliteration were female sex, a single SRS treatment, a higher margin dose, a higher isodose line, a deep AVM location, and a smaller AVM volume. The crude rate of post-SRS hemorrhage was 50% lower in the early (3.2%) than in the late (6.4%) obliteration cohorts, but this difference was not statistically significant (p = 0.248). The other outcomes of the early versus late obliteration cohorts were similar, with respect to symptomatic radiation-induced changes (RICs), cyst formation, and tumor formation.

CONCLUSIONS

Approximately one-quarter of pediatric AVMs that become obliterated after SRS will achieve this radiological endpoint within 24 months of initial SRS. The authors identified multiple factors associated with early obliteration, which may aid in prognostication and management. The overall risks of delayed hemorrhage, RICs, cyst formation, and tumor formation were not statistically different in patients with early versus late obliteration.

Clinical Outcomes of Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations in Pediatric Patients: Systematic Review and Meta-Analysis

BACKGROUND

Arteriovenous malformations (AVMs) in pediatric patients exhibit remarkable differences in terms of management and outcomes. Owing to a paucity of relevant data pertaining to AVMs in pediatric patients, special interest and investigation are required for an improved understanding of the available evidence by clinicians.

OBJECTIVE

To determine the clinical outcomes of single-session stereotactic radiosurgery (SRS) for AVMs in pediatric patients.

METHODS

A systematic literature review was performed to identify studies that reported the outcomes of SRS for AVMs in pediatric patients. Data pertaining to variables such as obliteration rate, post-SRS new hemorrhage rate, post-SRS new neurological deficit rate, and mortality rate were extracted and analyzed using meta-analysis techniques.

RESULTS

Based on pooled data from 20 studies with 1212 patients, single-session SRS resulted in complete obliteration in 65.9% (95% confidence interval [CI], 60.5%-71.1%; I2 = 66.5%) patients. Overall complication rate (including new hemorrhage, new neurodeficit, and mortality) was 8.0% (95% CI, 5.1%-11.5%; I2 = 66.4%). Post-SRS new neurological deficit rate was 3.1% (95% CI, 1.3%-5.4%; I2 = 59.7%), and post-SRS hemorrhage rate was 4.2% (95% CI, 2.5%-6.3%; I2 = 42.7%). There was no significant difference between studies disaggregated by treatment method (Gamma Knife [Elekta AB] vs other), treatment year (before year 2000 vs after year 2000), median AVM volume reported (≥3 vs <3 cm3), median dose reported (≥20 vs <20 Gy), or follow-up period (≥36 vs <36 mo).

CONCLUSION

Single-SRS is a safe treatment alternative that achieves high obliteration rates and acceptable complication rates for AVMs in pediatric patients.

The factors associated with hemorrhagic presentation in children with untreated brain arteriovenous malformation: a meta-analysis

OBJECTIVE Rupture of arteriovenous malformations (AVMs) would result in high mortality and prevalence of disability in pediatric patients. Decisions regarding the treatment of AVMs need to weigh the risk of rupture over the course of their natural history against the possibility of creating a lesion during treatment. Multiple factors have been proposed to predict hemorrhagic presentation of pediatric patients with AVMs. The aim of this meta-analysis was to evaluate the predictors of hemorrhagic presentation in pediatric patients with AVMs. METHODS The authors searched the PubMed and EMBASE databases. Studies reporting the predictors of hemorrhagic presentation in children with untreated brain AVMs were included. The predictive ability of identified predictors was assessed by odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS A higher risk of hemorrhagic presentation was found in AVMs with smaller size (< 3 cm, OR 2.97, 95% CI 1.94–4.54, p < 0.00001), deep venous drainage (OR 2.28, 95% CI 1.55–3.36, p < 0.0001), a single draining vein (OR 2.23, 95% CI 1.27–3.92, p = 0.005), a single feeder (OR 3.72, 95% CI 1.31–10.62, p = 0.01), a deep location (OR 1.82, 95% CI 1.22–2.72, p = 0.004), an infratentorial location (OR 2.25, 95% CI 1.19–4.26, p = 0.01), and diffuse morphology (OR 8.94, 95% CI 3.01–26.55, p < 0.0001). In addition, the AVMs with draining vein ectasia (OR 0.35, 95% CI 0.13–0.97, p = 0.04) and high Spetzler-Martin (SM) grade (OR 0.53, 95% CI 0.36–0.78, p = 0.001) had a lower risk of hemorrhagic presentation in pediatric patients. CONCLUSIONS Smaller AVMs, deep venous drainage, a single draining vein, a single feeder, deep/infratentorial location, diffuse morphology, and high SM grade were identified as positive predictors for hemorrhagic presentation. Particularly, patients with diffuse AVMs have a higher risk of hemorrhagic presentation than other factors and may need active treatments. However, factors such as age, sex, draining vein stenosis, and associated aneurysms were not associated with hemorrhagic presentation. ABBREVIATIONS AVM = arteriovenous malformation; CI = confidence interval; NOS = Newcastle-Ottawa Scale; OR = odds ratio; SM = Spetzler-Martin.

Radiotherapy Advances in Pediatric Neuro-Oncology

Radiation therapy (RT) represents an integral component in the treatment of many pediatric brain tumors. Multiple advances have emerged within pediatric radiation oncology that aim to optimize the therapeutic ratio—improving disease control while limiting RT-related toxicity. These include innovations in treatment planning with magnetic resonance imaging (MRI) simulation, as well as increasingly sophisticated radiation delivery techniques. Advanced RT techniques, including photon-based RT such as intensity-modulated RT (IMRT) and volumetric-modulated arc therapy (VMAT), as well as particle beam therapy and stereotactic RT, have afforded an array of options to dramatically reduce radiation exposure of uninvolved normal tissues while treating target volumes. Along with advances in image guidance of radiation treatments, novel RT approaches are being implemented in ongoing and future prospective clinical trials. As the era of molecular risk stratification unfolds, personalization of radiation dose, target, and technique holds the promise to meaningfully improve outcomes for pediatric neuro-oncology patients.

Gamma Knife Radiosurgery for Pediatric Arteriovenous Malformations: A Canadian Experience

BACKGROUND

Gamma Knife (GK) radiosurgery for pediatric arteriovenous malformations (AVM) of the brain presents a non-invasive treatment option. We report our institutional experience with GK for pediatric AVMs.

METHODS

We performed a retrospective review of all pediatric patients treated with GK for cerebral AVMs at our institution from November 2003 up to and including September 2014. Patient demographics, AVM characteristics, treatment parameters and AVM responses were recorded.

RESULTS

Nineteen patients were treated, with 4 lost to follow-up. The mean age was 14.2 years (range. 7-18 years), with 10 being males (52.6%). The mean AVM diameter and volume were 2.68 cm and 3.10 cm3 respectively. The mean Spetzler-Martin (SM) and Pollock grades of the treated AVMs were 2.4 and 0.99 respectively. The mean follow-up was 62 months. All AVMs treated demonstrated a response on follow-up imaging. Nine of 15 (60.0%) patients displayed obliteration of their AVMs. Nine of 11 patients with a minimum of 3 years follow-up (81.8%) displayed obliteration, with SM and Pollock grades correlating to the chance of obliteration in this group. Two patients developed post-GK edema requiring short course dexamethasone therapy. No other major complications occurred. No permanent complications occurred.

CONCLUSIONS

GK radiosurgery for pediatric AVMs offers a safe and effective treatment option, with low permanent complication rates during early follow-up.

Comparison of transcranial color-coded real-time sonography and contrast-enhanced color-coded sonography for detection and characterization of intracranial arteriovenous malformations

OBJECTIVES

To compare the diagnostic value of transcranial color-coded real-time sonography and contrast-enhanced color-coded sonography in detection and characterization of intracranial arteriovenous malformations.

METHODS

Thirty-one patients highly suspected to have an intracranial arteriovenous malformation were imaged with real-time and contrast-enhanced sonography. With digital subtraction angiography as the reference standard, the ability to detect the malformations and accurately determine their size and location was compared between the two imaging techniques.

RESULTS

One cavernous hemangioma and 30 intracranial arteriovenous malformations were imaged with real-time and contrast-enhanced sonography, which were confirmed by angiography. The detectability of contrast-enhanced sonography, especially for optimizing visualization of malformations located in the frontal, parietal, and occipital lobes, was higher than that of real-time sonography, although the overall number of malformations was too small to demonstrate significance. The sizes of the malformations (6 in the frontal lobe, 1 in the parietal lobe, and 1 in the occipital lobe) were underestimated by real-time sonography compared to angiography, whereas there was agreement in the sizes between contrast-enhanced sonography and angiography. The detection rates for the 30 arteriovenous malformations on contrast-enhanced and real-time sonography were 96.7% (29 of 30) and 70.0% (21 of 30), respectively (P = .008). Moreover, contrast-enhanced sonography was significantly superior to real-time sonography for detection of feeding arteries (59.5% [22 of 37] versus 83.7% [31 of 37]; P = .004). Although the feeding arteries showed increased peak systolic and end-diastolic velocities after contrast agent injection, there were no statistically significant differences in the velocities before and after injection.

CONCLUSIONS

Transcranial contrast-enhanced color-coded sonography is superior to color-coded real-time sonography for detection of intracranial arteriovenous malformations, particularly for lesions located in the frontal, parietal, and occipital lobes of the brain.

Clinico-radiological outcomes following gamma knife radiosurgery for pediatric arteriovenous malformations

PURPOSE

The aim of this study was to evaluate clinico-radiological outcomes following gamma knife radiosurgery (GKS) for pediatric arteriovenous malformations (AVMs).

METHODS

The present series included 39 children (3-17 years of age) who underwent GKS for cerebral AVMs between January 2002 and February 2008. Twenty-five patients presented with hemorrhages. The median AVM volume was 1.5 cm³, and the median marginal dose was 20 Gy. All patients continued to have follow-up for more than 24 months with serial magnetic resonance images (MRIs)/angiograms. Current school performance has been evaluated using a telephone survey answered by the patients' parents.

RESULTS

Follow-up angiograms, available in 34 patients, confirmed complete obliteration in 16 patients. Serial MRIs indicated obliteration of the nidus in one of five patients without angiography. The diffuse nidus structure and low marginal dose were significantly associated with incomplete obliteration. Twelve patients underwent a second GKS, and subsequent angiographies, available in six patients, demonstrated complete obliteration in two of them. Complications included new-onset seizures (n = 1), apraxia (n = 1), and temporal horn entrapment requiring a shunt operation (n = 1). School performance declined in 14 out of 32 patients. Both the AVM volume and modified AVM score were found to be reliable predictors of school performance.

CONCLUSIONS

The results of the present study substantiate the diffuse and other atypical features of pediatric AVMs as major determinants of treatment failure following GKS. Considering the apparent declination of school performance, future prospective studies would be required to investigate the possible late-effects of GKS on neuropsychological function.