What is the best therapeutic approach to a pediatric patient with a deep-seated brain AVM?

Comparative outcomes of arteriovenous malformations treatment in eloquent versus non-eloquent brain: A multicenter study with propensity-score weighting

BACKGROUND

Arteriovenous malformations (AVMs) are complex vascular anomalies with a high risk of hemorrhage and neurological deficits, especially when located in eloquent brain regions. The eloquence of an AVM location is a critical factor in the treatment planning, influencing both the risk of complications and long-term functional outcomes. This study aims to compare outcomes between eloquent and non-eloquent AVMs.

METHODS

This multicenter, retrospective study utilized data from the Multicenter International Study for Treatment of Brain AVMs (MISTA) consortium. Patients with eloquent and non-eloquent AVMs were compared on baseline characteristics, angiographic outcomes, and functional outcomes using the modified Rankin Scale (mRS). Propensity score weighting (IPTW) was applied to adjust for confounding variables.

RESULTS

The study included 1013 patients, with 498 (49.2%) AVMs located in eloquent regions and 515 (50.8%) in non-eloquent regions. In unadjusted analysis, eloquent AVMs had lower complete obliteration rates (67.6% vs 79.5%, OR: 0.53, 95% CI: 0.39-0.72, p < 0.001) and higher complication rates (24.5% vs 19.0%, OR: 1.38, 95% CI: 1.02-1.86, p = 0.03) compared to non-eloquent AVMs. After IPTW adjustment, eloquent AVMs continued to show significantly higher odds of overall complications (OR: 1.68, 95% CI: 1.12-2.52, p = 0.01) and symptomatic complications (OR: 1.77, 95% CI: 1.12-2.80, p = 0.01). Secondary analysis within the eloquent group indicated that embolization was linked to an elevated risk of complications. Surgery and radiosurgery showed comparable functional outcomes at last follow-up and complications rates with higher complete obliteration rates in surgery.

CONCLUSION

AVMs in eloquent brain areas present higher risks of complications and lower obliteration rates, emphasizing the need for cautious, individualized treatment planning. Within the eloquent group, embolization increased the risk of complications, while surgery and radiosurgery showed comparable functional outcomes at last follow-up and complication rates with higher complete obliteration rates in surgery. These findings highlight the importance of location in AVM management and support further research focusing on comparing treatment strategies for AVMs in eloquent brain areas.

Thalamic Arteriovenous Malformations: A Systematic Review of Presentation, Diagnostic Modalities, and Treatment Approaches

Thalamic arteriovenous malformations (AVMs) are rare, deep-seated vascular lesions associated with a high risk of hemorrhage and significant neurological deficits. Due to their complex anatomy, these lesions present unique challenges in management. Various therapeutic approaches, including microsurgical resection, stereotactic radiosurgery, and embolization, have been employed to address these challenges. This systematic review examines the clinical presentation, diagnostic modalities, treatment outcomes, and complications associated with thalamic AVMs. A comprehensive literature search was conducted in PubMed, Scopus, and Rayyan databases, focusing on studies reporting clinical outcomes of patients with thalamic AVMs. Eligible studies included those assessing treatment outcomes for surgical resection, stereotactic radiosurgery (SRS), and embolization. Data extraction and risk of bias assessments were performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Nineteen studies, comprising a total of 97 patients, were included. Radiosurgery was the most frequently employed treatment, with obliteration rates ranging from 66.7% to 82%, though it carried a risk of post-treatment complications such as rebleeding (5.9%) and neurological deficits (17%). Microsurgery achieved obliteration rates of up to 71%, but this was associated with significant perioperative risks. In comparison, radiosurgery demonstrated obliteration rates ranging from 66.7% to 82%, offering a balance between safety and efficacy for most patients. Embolization, though less commonly used, showed promise in select cases, while conservative management was effective for patients in whom surgery posed an excessive risk. The management of thalamic AVMs is multidisciplinary, with treatment decisions tailored to individual AVM characteristics, patient status, and risk profiles over time. Microsurgical resection remains an option for cases requiring immediate intervention.

Timing of Embolization, Radiosurgery, and Resection of Arteriovenous Malformations in Pediatric Patients: A Retrospective, Descriptive Study

OBJECTIVE

Cerebral arteriovenous malformations (AVMs) are a challenging pathology in pediatric patients, carrying a high risk of morbidity and mortality. Treatment modalities include resection, endovascular embolization, and stereotactic radiosurgery. There is currently no consensus favoring one modality over another. Timing of multimodal therapy with embolization/stereotactic radiosurgery and resection is not well explored in the literature. We present a series of pediatric patients with AVMs, with special attention directed to the timing of treatment.

METHODS

Electronic medical records of all pediatric patients (<18 years old at treatment) with AVMs treated at our institution were retrospectively reviewed after institutional review board approval. Demographic information, AVM characteristics, treatment variables, and outcomes were recorded.

RESULTS

In our cohort of 27 patients, 21 (77.8%) presented with a ruptured AVM. Of these patients, 6 (28.6%) had a Glasgow Coma Scale score of 3-10 and underwent treatment within 24 hours of presentation, and 10 (47.6%) with a Glasgow Coma Scale score of 12-15 were treated between 24 and 120 hours after presentation. The remaining 5 patients (23.8%) were treated 3 weeks to 14 months after AVM rupture. Regardless of rupture status, 96% of our cohort had a modified Rankin Scale score of 1-2 at most recent follow-up.

CONCLUSIONS

We present our institution's experience with pediatric AVMs, focusing on the timing of treatment. Based on our experience, early treatment of AVMs seems to be safe and effective regardless of rupture status.

Hypofractionated stereotactic radiotherapy in Spetzler Martin grades 4 and 5 arteriovenous malformations in the pediatric population: Is it a viable alternative?

OBJECTIVE

To analyze the outcomes of hypofractionated stereotactic radiotherapy (HFSRT) for Spetzler Martin grades 4 and 5 arteriovenous malformations (AVMs) in a pediatric population.

METHODS

Fourteen patients with Spetzler Martin (SM) grades IV and V large AVMs who underwent HFSRT between January 2013 and July 2019 were retrospectively reviewed. All patients received HFSRT at a dose of 30-36 Gy in 5 to 6 fractions. They were followed up annually with clinical and imaging assessments to evaluate obliteration rates.

RESULTS

The median age at presentation was 15 years (range 8-21 years). Ten (71%) were SM grade 4 AVMs and the rest were SM grade 5 AVMs. The majority presented with headache (8 [57%]), and 3 (21%) presented with bleeding. The median nidus volume was 39.4 cc (IQR, 31.4-52.4). Two (14%) patients had infratentorial AVMs. All of them had deep venous drainage. The median clinical follow-up duration was 75 months (range 31-107 months). There was complete obliteration of the nidus in 3 (21%) patients with a median time to obliteration of 39 months. HFSRT resulted in a reduction of the AVM volume to 12 cc or less in nearly 70% of patients. None of the patients experienced re-bleeding. 79% reported an improvement in their symptoms.

CONCLUSION

HFSRT is a highly effective treatment for high-grade AVMs in children, which can result in either complete elimination or significant reduction of the nidus volume or make it suitable for additional treatment, such as single-session stereotactic radiosurgery (SRS).

Natural history and treatment of deep-seated brain arteriovenous malformations in pediatric patients

OBJECTIVE

Pediatric deep brain arteriovenous malformations (bAVMs) represent a unique management challenge given their higher cumulative risk of hemorrhage as well as a higher risk of treatment. Better understanding of hemorrhage risk in this patient population will lead to a better decision-making process for patient management.

METHODS

The authors retrospectively reviewed their institutional bAVM database from 1990 to 2019 and included patients younger than 21 years who had deep-seated bAVMs. They present the annual hemorrhage risk, during the natural history and after treatment, and functional outcomes.

RESULTS

Thirty-one pediatric patients were included in this study (13 males and 18 females) with a mean age of 11.8 (SD 4.4) years. The most frequent presenting symptoms were headache (54.8%), weakness (38.7%), and seizure (22.6%). The mean follow-up duration was 13.14 (SD 12.5) years, during which 7 (22.6%) AVMs were obliterated, 10 (32.3%) individuals experienced hemorrhage, and the modified Rankin Scale score worsened in 8 (25.8%) patients. The annual natural history risk of hemorrhage was 3.24% per patient, and the overall annual hemorrhage risk after treatment was 1.98% per patient. In particular, the risk was reduced to 0.64% per patient in the stereotactic radiosurgery (SRS) group. Non-White race showed a trend of higher rupture at presentation (OR 5 [95% CI 0.84-41.68], p = 0.09). Female sex was associated with higher odds (OR 13.076 [95% CI 1.424-333.591], p = 0.048) and SRS was associated with lower odds (OR 0.122 [95% CI 0.011-0.862], p = 0.049) of follow-up hemorrhage.

CONCLUSIONS

Given the substantial cumulative risk of lifelong hemorrhagic stroke in pediatric patients, timely definitive treatment is warranted. SRS may be beneficial when the risk-benefit profile is deemed acceptable.

The 20th Gray lecture 2019: health and heavy ions

OBJECTIVE

Particle radiobiology has contributed new understanding of radiation safety and underlying mechanisms of action to radiation oncology for the treatment of cancer, and to planning of radiation protection for space travel. This manuscript will highlight the significance of precise physical and biologically effective dosimetry to this translational research for the benefit of human health.This review provides a brief snapshot of the evolving scientific basis for, and the complex current global status, and remaining challenges of hadron therapy for the treatment of cancer. The need for particle radiobiology for risk planning in return missions to the Moon, and exploratory deep-space missions to Mars and beyond are also discussed.

METHODS

Key lessons learned are summarized from an impressive collective literature published by an international cadre of multidisciplinary experts in particle physics, radiation chemistry, medical physics of imaging and treatment planning, molecular, cellular, tissue radiobiology, biology of microgravity and other stressors, theoretical modeling of biophysical data, and clinical results with accelerator-produced particle beams.

RESULTS

Research pioneers, many of whom were Nobel laureates, led the world in the discovery of ionizing radiations originating from the Earth and the Cosmos. Six radiation pioneers led the way to hadron therapy and the study of charged particles encountered in outer space travel. Worldwide about 250,000 patients have been treated for cancer, or other lesions such as arteriovenous malformations in the brain between 1954 and 2019 with charged particle radiotherapy, also known as hadron therapy. The majority of these patients (213,000) were treated with proton beams, but approximately 32,000 were treated with carbon ion radiotherapy. There are 3500 patients who have been treated with helium, pions, neon or other ions. There are currently 82 facilities operating to provide ion beam clinical treatments. Of these, only 13 facilities located in Asia and Europe are providing carbon ion beams for preclinical, clinical, and space research. There are also numerous particle physics accelerators worldwide capable of producing ion beams for research, but not currently focused on treating patients with ion beam therapy but are potentially available for preclinical and space research. Approximately, more than 550 individuals have traveled into Lower Earth Orbit (LEO) and beyond and returned to Earth.

CONCLUSION

Charged particle therapy with controlled beams of protons and carbon ions have significantly impacted targeted cancer therapy, eradicated tumors while sparing normal tissue toxicities, and reduced human suffering. These modalities still require further optimization and technical refinements to reduce cost but should be made available to everyone in need worldwide. The exploration of our Universe in space travel poses the potential risk of exposure to uncontrolled charged particles. However, approaches to shield and provide countermeasures to these potential radiation hazards in LEO have allowed an amazing number of discoveries currently without significant life-threatening medical consequences. More basic research with components of the Galactic Cosmic Radiation field are still required to assure safety involving space radiations and combined stressors with microgravity for exploratory deep space travel.

ADVANCES IN KNOWLEDGE

The collective knowledge garnered from the wealth of available published evidence obtained prior to particle radiation therapy, or to space flight, and the additional data gleaned from implementing both endeavors has provided many opportunities for heavy ions to promote human health.