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Background: Progressive isolated optic nerve glioma (ONG) in children is a rare disease, treated with various modalities. A global treatment consensus is not available., Methods: We conducted a national retrospective multicenter cohort study (1995-2020) to investigate how different treatment strategies impact outcome for ONG in children, by assessing treatment responses to systemic anticancer therapy (SAT), surgery, and radiotherapy for ONG. The primary endpoints included changes in best-corrected visual acuity (BCVA) and tumor volume (TV) on MRI, both evaluated at the start and end of therapy and at long-term follow up., Results: A total of 21 ONGs (20 patients) received SAT (n = 14 (66.7%)), surgery (n = 4 (19.0%)), and radiotherapy (n = 3 (14.3%)). After SAT BCVA stabilized or improved in 66.6% (n = 4) and the TV decreased by a median of 45.1% (range: -88.6% to +31.5%) (n = 13). Before resection two eyes were already blind. After resection BCVA decreased to blindness in one eye. In total all four eyes were blind after resection. After first-line RT BCVA decreased in 66.7% of ONG to counting fingers or less, TV increased <3 months after RT by a median of 47.3% (range: -42.8% to +245.1%) (n = 3), followed by a long-term decrease of 94.4 and 13.8% (n = 2), respectively., Conclusion: SAT appears to be the preferred modality for progressive ONG in case of potential rescue of visual functions. Complete resection of ONG appears effective to reduce proptosis in case of preexisting blindness. The use of radiotherapy requires careful consideration due to the risk of severe visual impairment and secondary disease., (© 2024 The Author(s). Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Background: Optic pathway gliomas (OPG) are rare tumors in children. Lesion extent, visual functions, neurofibromatosis 1 (NF1), and age are factors that guide treatment. This study evaluates the clinical characteristics, treatment, and outcome of children and adolescents with OPG treated over a 31-year period in a single center., Methods: Ninety-five patients with OPG diagnosed between January 1990 and December 2021 were retrospectively evaluated. First-line chemotherapy regimen consisted of vincristine and carboplatinum for 1 year. Radiotherapy was not used as first-line treatment and tried to be avoided in the ones who progressed after first-line treatment., Results: Ninety-five children (44 male, 51 female) with a median age of 52 (1-216) months were evaluated. Sixty-three (66.3%) had NF1 and 10 (10,5%) diencephalic syndrome. The most common presenting symptoms were visual abnormalities and/or proptosis, nistagmus, and behavioral changes. Twenty-one (22.1%) patients with NF1 had stable disease throughout the follow-up period and received no treatment. Sixty-three of 74 patients received treatment at diagnosis and 11 due to progression during follow-up. Only one adolescent received radiotherapy at progression. Patients who progressed, received further line systemic treatment (vinblastine; bevacizumab; vincristine-cisplatinum-etoposide). Ten-year overall survival in all patients, in patients with NF1, and without NF1 were 97.2%, 98%, and 95.8% (p > .05), respectively; 10-year progression-free survival (PFS) in all patients, in patients with NF1, and without NF1 were 71.6%, 85.7%, and 54.2% (p = .001), respectively., Conclusions: In children with symptomatic/progressive OPG, chemotherapy consisting of vincristine-carboplatinum (VC) is effective. Radiotherapy may be avoided, especially in patients with NF1., (© 2024 The Author(s). Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Purpose: We examined regression patterns in pediatric optic pathway gliomas (OPGs) after proton beam therapy (PBT) and evaluated local control and visual outcomes., Methods: A total of 42 brain magnetic resonance imaging (MRI) scans from seven consecutive sporadic OPGs that were initially treated with chemotherapy and received PBT between June 2007 and September 2016 at the National Cancer Center, Korea were analyzed. Patients underwent brain MRI regularly before and after PBT. Total tumor, cystic lesion, and solid enhancing lesion area delineation and volume calculations were performed on gadolinium-enhanced T1-weighted MRI using Eclipse version 13, Varian., Results: The median follow-up period after PBT was 70 months (range 47-88). The median age at the time of PBT was 7 years (range 4-16) and the median duration of chemotherapy before referral to PBT center was 25 months (range 3-70). The median time to the greatest increase in cystic volume was 32 months (range 12-43) after PBT. Solid enhancing lesion volume gradually decreased throughout the follow-up period. On an individual basis, total volume change was varied. However, on average, it regressed, although at a slower rate than solid enhancing lesion volume did. The local control rate was 85.7% (5-year progression-free survival rate, 80%; 5-year overall survival rate, 100%) and the rate of vision preservation was 71.4% (five of seven patients)., Conclusion: The regression patterns in pediatric OPGs after PBT involve significant cystic change. Therefore, total volume is not appropriate for evaluating response. Care by a multidisciplinary team is necessary to manage clinical symptoms related to radiologic changes., (© 2021 Wiley Periodicals LLC.)

Background: To develop an auxiliary GPU-accelerated proton therapy (PT) dose and LET d engine for the IBA Proteus®ONE PT system. A pediatric low-grade glioma case study is reported using FRoG during clinical practice, highlighting potential treatment planning insights using variable RBE dose (D vRBE ) and LET d as indicators for clinical decision making in PT., Methods: The physics engine for FRoG has been modified for compatibility with Proteus®ONE PT centers. Subsequently, FRoG was installed and commissioned at NPTC. Dosimetric validation was performed against measurements and the clinical TPS, RayStation (RS-MC). A head patient cohort previously treated at NPTC was collected and FRoG forward calculations were compared against RS-MC for evaluation of 3D-Γ analysis and dose volume histogram (DVH) results. Currently, treatment design at NPTC is supported with fast variable RBE and LET d calculation and is reported in a representative case for pediatric low-grade glioma., Results: Simple dosimetric tests against measurements of iso-energy layers and spread-out Bragg Peaks in water verified accuracy of FRoG and RS-MC. Among the patient cohort, average 3D-Γ applying 2%/2 mm, 3%/1.5 mm and 5%/1 mm were > 97%. DVH metrics for targets and OARs between FRoG and RayStation were in good agreement, with ∆D 50,CTV and ∆D 2,OAR both ⪅1%. The pediatric case report demonstrated implications of different beam arrangements on D vRBE  and LET d distributions. From initial planning in RayStation sharing identical optimization constraints, FRoG analysis led to plan selection of the most conservative approach, i.e., minimized D vRBE,max and LET d,max in OARs, to avoid optical system toxicity effects (i.e., vision loss)., Conclusion: An auxiliary dose calculation system was successfully integrated into the clinical workflow at a Proteus®ONE IBA facility, in excellent agreement with measurements and RS-MC. FRoG may lead to further insight on D vRBE and LET d implications to help clinical decision making, better understand unexpected toxicities and establish novel clinical procedures with metrics currently absent from the standard clinical TPS., (© 2021. The Author(s).)

Optic nerve glioma is a rather rare tumor. It predominantly arises in pediatric patients, including those with type I neurofibromatosis. This neoplasm is accompanied by decreased visual function and exophthalmos. Treatment strategy is individualized depending on age, volume and spread of tumor, as well as severity of clinical manifestations. Possible treatment options are surgical resection, chemotherapy, radiotherapy and their combination. Radiotherapy can be recommended for patients with intact visual functions, no severe proptosis and trophic lesions. Classic fractionation mode is used as a standard. Currently, the possibility of hypofractionated irradiation is being considered., Objective: To evaluate safety and efficacy of hypofractionated radiotherapy in patients with optic nerve glioma., Material and Methods: Sixteen patients with optic nerve gliomas underwent hypofractionated stereotactic irradiation (CyberKnife) between May 2014 and October 2019. Single focal dose was 5.5 Gy. There were 5 fractions up to total focal dose of 27.5 Gy. The sample enrolled 14 children with a median age of 4 years (range 23 months - 13 years) and 2 adults aged 47 and 66 years, respectively. Median of tumor volume was 2.77 cm 3 (range 1.69-10.01 cm 3 )., Results: Tumor growth control was achieved in all patients, partial remission was observed in 5 (32%) patients. None patient had deterioration of visual function. Improvement of visual acuity was noted in 3 (19%) cases. Visual field enlargement occurred in 4 (67%) out of 6 patients who were preoperatively examined. After irradiation, proptosis decreased by ≥ 1 mm in 9 (60%) out of 15 patients.