Fatal glioblastoma after Gamma Knife radiosurgery for arteriovenous malformation in a child

Effect of embolization before stereotactic radiosurgery for brain arteriovenous malformations: a case-control study with propensity score matching

OBJECTIVE

The aim of this study was to evaluate whether endovascular embolization prior to stereotactic radiosurgery (SRS) has a negative impact on nidus obliteration for patients with arteriovenous malformations (AVMs).

METHODS

A total of 704 eligible patients with AVM who did not undergo prior surgery or radiotherapy were evaluated. Of these patients, 593 were treated with SRS only, and 111 were treated with embolization followed by SRS (E+SRS). Most patients in the E+SRS group (88%) underwent embolization with n-butyl-2-cyanoacrylate. In the comparison of radiosurgical outcomes between patients treated with SRS only and E+SRS, these groups were matched in a 1:1 ratio using propensity score matching to eliminate differences in basic characteristics. The primary outcome was to compare the nidus obliteration rates between the SRS-only and E+SRS groups. The secondary outcomes were the comparison of cumulative hemorrhage rates and the incidence of cyst formation or chronic encapsulated hematoma after SRS between these groups.

RESULTS

In the unmatched cohorts, the actuarial 3-, 5-, and 8-year nidus obliteration rates after a single SRS session were 49.6%, 69.4%, and 74.1% in the SRS-only group, respectively, and 30.7%, 50.9%, and 68.6% in the E+SRS group, respectively (p = 0.001). In the matched cohort of 98 patients in each group, the rates were 47.1%, 62.0%, and 69.6% in the SRS-only group and 32.5%, 55.3%, and 75.0% in the E+SRS group, respectively (p = 0.24). There was no significant difference in either cumulative hemorrhage or the incidence of cyst formation or chronic encapsulated hematoma between the groups.

CONCLUSIONS

Pre-SRS embolization did not affect nidus obliteration rates, cumulative hemorrhage rates, or the incidence of cyst formation or chronic encapsulated hematoma as late adverse radiation effects in patients with AVM treated with SRS.

Long-Term Risks of Hemorrhage and Adverse Radiation Effects of Stereotactic Radiosurgery for Brain Arteriovenous Malformations

BACKGROUND

The information about long-term risks of hemorrhage and late adverse radiation effects (AREs) after stereotactic radiosurgery for brain arteriovenous malformations (AVMs) is lacking.

OBJECTIVE

To evaluate the long-term risks of hemorrhage and late ARE rates in patients with AVM treated with Gamma Knife surgery (GKS).

METHODS

We examined 1249 patients with AVM treated with GKS. The Spetzler-Martin grade was I in 313 patients (25%), II in 394 (32%), III in 458 (37%), and IV/V in 84 (7%). The median treatment volume was 2.5 cm3, and the median marginal dose was 20 Gy.

RESULTS

The median follow-up period was 61 months. The 5- and 10-year nidus obliteration rates were 63% and 82%, respectively. The 5- and 10-year cumulative hemorrhage rates were 7% and 10%, respectively. The annual hemorrhage rate was 1.5% for the first 5 years post-GKS, which decreased to 0.5% thereafter. During the follow-up period, 42 symptomatic cyst formations/chronic encapsulated hematomas ([CFs/CEHs], 3%) and 3 radiation-induced tumors (0.2%) were observed. The 10- and 15-year cumulative CF/CEH rates were 3.7% and 9.4%, respectively.

CONCLUSION

GKS is associated with reduced hemorrhage risk and high nidus obliteration rates in patients with AVM. The incidence of late AREs tended to increase over time. The most common ARE was CF/CEH, which can be safely removed; however, careful attention should be paid to the long-term development of fatal radiation-induced tumors.

Glioblastoma multiforme as a secondary malignancy following stereotactic radiosurgery of a meningioma: case report

The documentation and exact incidence of stereotactic radiosurgery (SRS)-induced neoplasia is not well understood, with most literature restricted to single case reports and single-center retrospective reviews. The authors present a rare case of radiosurgery-induced glioblastoma multiforme (GBM) following radiosurgical treatment of a meningioma. A 74-year-old patient with a sporadic meningioma underwent radiosurgery following surgical removal of a WHO grade II meningioma. Eighteen months later she presented with seizures, and MRI revealed an intraaxial tumor, which was resected and proven to be a glioblastoma. As far as the authors are aware, this case represents the third case of GBM following SRS for a meningioma. This report serves to increase the awareness of this possible complication following SRS. The possibility of this rare complication should be explained to patients when obtaining their consent for radiosurgery.

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.

Long-Term Outcomes for Pediatric Patients with Brain Arteriovenous Malformations Treated with Gamma Knife Radiosurgery, Part 2: The Incidence of Cyst Formation, Encapsulated Hematoma, and Radiation-Induced Tumor

OBJECTIVE

Long-term data about the incidence of late adverse radiation effects (AREs) in pediatric brain arteriovenous malformations (AVMs) treated with Gamma Knife radiosurgery (GKRS) are lacking. This study addresses the incidence of late AREs, including cyst formation (CF), chronic encapsulated hematoma (CEH), and radiation-induced tumor, in pediatric patients with AVM treated with GKRS.

METHODS

This is a single-institutional study involving pediatric patients with AVM who underwent GKRS between 1991 and 2014. Among 201 pediatric patients with AVM (age ≤15 years), 189 who had at least 12 months of follow-up were assessed in this study. The median treatment volume was 2.2 cm³, and the median marginal dose was 20 Gy.

RESULTS

The mean follow-up period was 136 months. During the follow-up period, symptomatic radiation-induced perilesional edema was found in 5 patients (3%), CFs in 7 patients (4%), CEHs in 7 patients (4%), and radiation-induced tumors in 2 patients (1%). The cumulative incidences of late AREs including CF, CEH, and radiation-induced tumor were 1.2% at 5 years, 5.2% at 8 years, 6.1% at 10 years, 7.2% at 15 years, and 17.0% at 20 years. In the multivariate analysis, treatment volume alone was a significant factor for late AREs (P < 0.001; hazard ratio, 1.111).

CONCLUSIONS

GKRS is a reasonable treatment option for pediatric AVMs to prevent future intracranial hemorrhages, particularly in the eloquent regions. However, considerable attention should be paid to late AREs such as CFs, CEHs, and radiation-induced tumors because of longer life expectancy in pediatric patients.

Comparison of the Long-term Efficacy and Safety of Gamma Knife Radiosurgery for Arteriovenous Malformations in Pediatric and Adult Patients

It is debated whether the efficacy and long-term safety of gamma knife radiosurgery (GKRS) for arteriovenous malformations (AVMs) differs between adult and pediatric patients. We aimed to clarify the long-term outcomes of GKRS in pediatric patients and how they compare to those in adult patients. We collected data for 736 consecutive patients with AVMs treated with GKRS between 1990 and 2014 and divided the patients into pediatric (age < 20 years, n = 144) and adult (age ≥ 20 years, n = 592) cohorts. The mean follow-up period in the pediatric cohort was 130 months. Compared to the adult patients, the pediatric patients were significantly more likely to have a history of hemorrhage (P < 0.001). The actuarial rates of post-GKRS nidus obliteration in the pediatric cohort were 36%, 60%, and 87% at 2, 3, and 6 years, respectively. Nidus obliteration occurred earlier in the pediatric cohort than in the adult cohort (P = 0.015). The actuarial rates of post-GKRS hemorrhage in the pediatric cohort were 0.7%, 2.5%, and 2.5% at 1, 5, and 10 years, respectively. Post-GKRS hemorrhage was marginally less common in the pediatric cohort than in the adult cohort (P = 0.056). Cyst formation/encapsulated hematoma were detected in seven pediatric patients (4.9%) at a median post-GKRS timepoint of 111 months, which was not significantly different from the rate in the adult cohort. Compared to adult patients, pediatric patients experience earlier therapeutic effects from GKRS for AVMs, and this improves long-term outcomes.

Angioarchitectural Risk Factors for Hemorrhage and Clinical Long-Term Outcome in Pediatric Patients with Cerebral Arteriovenous Malformations

BACKGROUND

Intracranial arteriovenous malformation (AVM) in children is a rare diagnosis. Little is known about factors determining AVM rupture and appropriate treatment strategies to prevent hemorrhage and associated disability. Available data suggest that children are subject to an increased risk for AVM rupture compared with adults.

METHODS

In 46 pediatric patients with AVM, demographic factors, clinical presentation, angioarchitectural features, and treatment regimens as well as clinical and radiologic outcomes were retrospectively analyzed. First-line treatment option was microsurgical resection of the disease, with or without preoperative embolization.

RESULTS

Twenty-four boys (52.2%) and 22 girls (47.8%) with a mean age on admission of 12.4 years (4-18 years) were included. Mean follow-up was 4 years (median, 1.5; range, 0.1-16.4). Thirty-one children presented with intracerebral hemorrhage (67.4%). Small AVMs (<3 cm) ruptured in 83.3% (n = 25) and were shown to be more prone to hemorrhage than larger ones (P < 0.01). Small AVM size (P < 0.01; odds ratio [OR], 0.12; 95% confidence interval [CI] 0.02-0.59) and exclusive deep venous drainage (P < 0.01; OR, 29.74; 95% CI, 2.45-4445.34) were independent risk factors for hemorrhage in the presented cohort. Good long-term outcome was associated with a high score on the Glasgow Coma Scale on admittance (P < 0.05; OR, 0.148; 95% CI, 0.03-0.73).

CONCLUSIONS

Two-thirds of children with AVM are admitted with intracerebral hemorrhage. Microsurgical resection was successful as confirmed by radiologic studies in 95%, and 79.5% of patients presented in a good clinical condition on follow-up (modified Rankin Scale 0 or 1). Microsurgical treatment is recommended if the lesion is accessible and angioarchitectural risk factors favor definitive treatment.

Hybrid Microscopic-Endoscopic Surgery for Craniopharyngioma in Neurosurgical Suite: Technical Notes

OBJECTIVE

The best chance of curing craniopharyngioma is achieved by microsurgical total resection; however, its location adjacent to critical structures hinders complete resection without neurologic deterioration. Unrecognized residual tumor within microscopic blind spots might result in tumor recurrences. To improve outcomes, new techniques are necessary to visualize tissue within these blind spots. We examined the success of hybrid microscopic-endoscopic neurosurgery for craniopharyngioma in a neurosurgical suite.

METHODS

Four children with craniopharyngiomas underwent microscopic resection. When the neurosurgeon was confident that most of the visible tumor was removed but was suspicious of residual tumor within the blind spot, he or she used an integrated endoscope-holder system to inspect and remove any residual tumor. Two ceiling monitors were mounted side by side in front of the surgeon to display both microscopic and endoscopic views and to view both monitors simultaneously.

RESULTS

Surgery was performed in all patients via the frontobasal interhemispheric approach. Residual tumors were observed in the sella (2 patients), on the ventral surface of the chiasm and optic nerve (1 patient), and in the third ventricle (1 patient) and were resected to achieve total resection. Postoperatively, visual function was improved in 2 patients and none exhibited deterioration related to the surgery.

CONCLUSIONS

Simultaneous microscopic and endoscopic observation with the use of dual monitors in a neurosurgical suite was ergonomically optimal for the surgeon to perform microsurgical procedures and to avoid traumatizing surrounding vessels or neural tissues. Hybrid microscopic-endoscopic neurosurgery may contribute to safe, less-invasive, and maximal resection to achieve better prognosis in children with craniopharyngioma.

The long-term outcomes of radiosurgery for arteriovenous malformations in pediatric and adolescent populations

OBJECT Although stereotactic radiosurgery (SRS) has been accepted as a therapeutic option for arteriovenous malformations (AVMs) in children and adolescents, substantial data are still lacking regarding the outcomes of SRS for AVMs in this age group, especially long-term complications. This study aimed to clarify the long-term outcomes of SRS for the treatment of AVM in pediatric patients aged ≤ 18 years. METHODS Outcomes of 116 patients who were aged 4-18 years when they underwent SRS between 1990 and 2009 at the study institute were analyzed retrospectively. RESULTS The median follow-up period after SRS was 100 months, with 6 patients followed up for more than 20 years. Actuarial obliteration rates at 3 and 5 years after SRS were 68% and 88%, respectively. Five hemorrhages occurred in 851 patient-years of follow-up. The annual bleeding rate after SRS before obliteration was calculated as 1.3%, which decreased to 0.2% after obliteration. Shorter maximum nidus diameter (p = 0.02) and higher margin dose (p = 0.03) were associated with a higher obliteration rate. Ten patients experienced adverse events after SRS. Of them, 4 patients presented with delayed complications years after SRS (range 9-20 years after SRS). CONCLUSIONS SRS can reduce the risk of hemorrhage in pediatric and adolescent AVMs, with an acceptable risk of complications in the long term. However, adverse events such as expanding hematoma and radiation necrosis that can occur after substantial follow-up should be taken into account at the time that treatment decisions are made and informed consent is obtained.

Molecular and cellular biology of cerebral arteriovenous malformations: a review of current concepts and future trends in treatment

OBJECT

Arteriovenous malformations (AVMs) are classically described as congenital static lesions. However, in addition to rupturing, AVMs can undergo growth, remodeling, and regression. These phenomena are directly related to cellular, molecular, and physiological processes. Understanding these relationships is essential to direct future diagnostic and therapeutic strategies. The authors performed a search of the contemporary literature to review current information regarding the molecular and cellular biology of AVMs and how this biology will impact their potential future management.

METHODS

A PubMed search was performed using the key words "genetic," "molecular," "brain," "cerebral," "arteriovenous," "malformation," "rupture," "management," "embolization," and "radiosurgery." Only English-language papers were considered. The reference lists of all papers selected for full-text assessment were reviewed.

RESULTS

Current concepts in genetic polymorphisms, growth factors, angiopoietins, apoptosis, endothelial cells, pathophysiology, clinical syndromes, medical treatment (including tetracycline and microRNA-18a), radiation therapy, endovascular embolization, and surgical treatment as they apply to AVMs are discussed.

CONCLUSIONS

Understanding the complex cellular biology, physiology, hemodynamics, and flow-related phenomena of AVMs is critical for defining and predicting their behavior, developing novel drug treatments, and improving endovascular and surgical therapies.

Glioblastoma after AVM radiosurgery. Case report and review of the literature

BACKGROUND

Stereotactic radiosurgery (SRS) is considered to be a relatively safe procedure in cerebral arteriovenous malformation management. There are very few reported cases of SRS-associated/induced malignancies.

METHODS

We show the case of a 21-year-old female who presented with a 21-mm(3) ruptured AVM in the right mesial frontocallosal region. Embolization and/or radiosurgery was proposed. She preferred radiosurgery. The AVM was treated with CyberKnife(®) SRS.

RESULTS

She presented behavior changes 6 years after SRS. MRI showed a right subcortical frontal lesion with increased perfusion, more consistent with high-grade glioma. The lesion's center was within the irradiated region of the previous SRS, having received an estimated radiation dose of 4 Gy. Pathological examination noted a hypercellular tumor showing astrocytic tumor cells with moderate pleomorphism in a fibrillary background, endothelial proliferation, and tumor necrosis surrounded by perinecrotic pseudopalisades. Numerous mitotic figures were seen. The appearances were those of glioblastoma, WHO grade IV, with neuronal differentiation. SRS-associated/-induced GBM after treatment of a large AM is exceptional. SRS-associated/-induced malignancies are mostly GBMs and occur on average after a latency of 9.4 years, within very low-dose peripheral regions as well as the full-dose regions; 33.3 % of patients were under 20 years at the time of SRS, and in 66 % the lesion treated was a vascular pathology.

CONCLUSION

Although it is unlikely that the risk of radiation-induced cancer will change the current standard of practice, patients must be warned of this potential possibility before treatment.