Our cohort of 174 pediatric patients with low-grade glioma demonstrated progression-free survival and overall survival rates of 84% and 92%, respectively, after proton therapy. These survival rates are similar to those of contemporary photon cohorts. Data from this prospective study inform radiation technique and overall patient management for the most common pediatric brain tumor. Purpose: Dosimetric studies show that proton therapy can reduce the low/intermediate radiation dose to uninvolved tissue in children with low-grade glioma (LGG). For this reason, LGG is the fourth most common pediatric tumor treated with proton therapy, yet clinical outcome data on efficacy and toxicity are limited. Methods and Materials: We reviewed the medical records of 174 children (21 years old) with nonmetastatic LGG enrolled on a prospective protocol and treated with proton therapy between 2007 and 2017. We assessed clinical outcomes and toxicity and analyzed patient, tumor, and treatment-related variables. Results: The median age was 10.2 years (range, 2-21). Fifty-eight percent of tumors were World Health Organization grade 1 and 30% were grade 2; 12% were diagnosed on imaging characteristics alone. The most common histology was pilocytic astrocytoma (47%). The most common tumor subsites were diencephalon/optic pathway (52%), caudal brainstem (16%), and cerebellum (13%). Forty-two percent received chemotherapy before radiation therapy. The median follow-up was 4.4 years. The 5year actuarial rates of local control, progression-free survival, and overall survival were 85% (95% confidence interval [CI], 78%-90%), 84% (95% CI, 77%-89%), and 92% (95% CI, 85%-95%), respectively. On univariate analysis, brainstem/spinal cord tumor location (62% vs 90% elsewhere) and dose <54 GyRBE (67% vs 91% for 54 GyRBE) were associated with inferior local control (P < .01 for both). Twenty-two patients (12.6%) experienced acute nausea or vomiting requiring ondansetron; 2 patients (1.1%) required corticosteroids. Serious toxicities (4% of patients)

This series of proton therapy for pediatric intracranial ependymoma demonstrates disease control comparable to photon series without unexpected toxicity. Subtotal resection and male sex were associated with inferior disease control. Additional follow-up to quantify the expected reductions in late toxicity with proton therapy is ongoing.

Pediatric intracranial aneurysms are exceedingly rare and account for less than 5% of all intracranial aneurysms. Open surgery to treat such aneurysms has been shown to be more durable than endovascular techniques, and durability of treatment is particularly important in the pediatric population. Over the past 2 decades, however, a marked shift in aneurysm treatment from open surgery toward endovascular procedures has occurred for adults. The authors describe their early experience in treating 3 unruptured pediatric brain aneurysms using the Pipeline embolization device (PED). The first patient, a girl with Majewski osteodysplastic primordial dwarfism Type II who was harboring multiple intracranial aneurysms, underwent two flow diversion procedures for a vertebrobasilar aneurysm and a supraclinoid internal carotid artery aneurysm. The second patient underwent PED placement on a previously coiled but enlarging posterior communicating artery aneurysm. All procedures were uneventful, with no postsurgical complications, and led to complete angiographic obliteration of the aneurysms. To the authors' knowledge, this is the first series of flow diversion procedures in children reported in the medical literature. While flow diversion is a new and relatively untested technology in children, outcomes in adults have been promising. For challenging lesions in the pediatric population, flow diversion may have a valuable role as a well-tolerated, safe treatment with durable results. Many issues remain to be addressed, such as the durability of flow diverters over a very long follow-up and vessel response to growth in the presence of an endoluminal device.