Optical Coherence Tomography Identifies Visual Pathway Involvement Earlier than Visual Function Tests in Children with MRI-Verified Optic Pathway Gliomas

This study investigates whether optical coherence tomography (OCT) could add useful information in the examination of children with optic pathway glioma (OPG) at high risk of developing vision loss. For this purpose, the relationship between ganglion cell-inner plexiform layer (GC-IPL) thickness and visual function, evaluated with tests of visual acuity (VA) and visual field (VF), as well as tumor site according to magnetic resonance imaging (MRI), were examined in a geographically defined group of children with OPG. Methods: Children aged <18 years with OPG underwent ophthalmic examination including VA, VF (Zeiss HFA perimetry) and OCT imaging (Zeiss Cirrus HD-OCT). Results: Out of 51 patients included, 45 provided 77 eyes with MRI-verified OPG, and 19 patients provided 25 eyes without OPG. Significant correlations were found between GC-IPL, VF and VA (p < 0.001). The GC-IPL pattern loss corresponded in 95% to VF defects and in 92% to MRI findings. Conclusions: Our study indicates that GC-IPL measures could serve as an early marker of vision-threatening changes related to OPG and as a valuable link between MRI and visual function tests. Thinning of GC-IPL and differences in topography between eyes are strong indicators of and predictive of vision loss related to OPG.

Tumor load rather than contrast enhancement is associated with the visual function of children and adolescents with optic pathway glioma – a retrospective Magnetic Resonance Imaging study

Introduction Optic pathway gliomas are often asymptomatic tumors occurring in children with neurofibromatosis type 1 (NF1 + OPG) or sporadically (spOPG). Treatment is usually prompted by visual loss and/or tumor progression on MRI. The aim of this study was to investigate the relationship between visual acuity (VA), tumor growth, and contrast enhancement to provide more distinct indications for the administration of gadolinium-based contrast agents. Methods Tumor load was retrospectively measured and enhancement semi-quantitatively scored on 298 MRIs of 35 patients (63% NF1 + OPG). Spearman rank correlation between tumor load and enhancement was calculated and a linear mixed model used to examine the influence of tumor load and enhancement on corresponding VA tests (LogMAR). Results The optic nerve width in NF1 + OPGs was strongly associated with VA (regression coefficient 0.75; confidence interval 0.61—0.88), but weakly with enhancement (0.06; −0.04—0.15). In spOPGs, tumor volume and optic nerve width were more relevant (0.31; −0.19—0.81 and 0.39; 0.05—0.73) than enhancement (0.09; −0.09—0.27). Conclusions Tumor load measures may be more relevant for the surveillance of optic pathway gliomas than enhancement, given that VA is the relevant outcome parameter. Regular contrast administration should therefore be questioned in these patients.

Spontaneous Regression of Tumor in an Optic Pathway Glioma Patient With Diencephalic Syndrome: Case Report and Literature Review

Background: Diencephalic syndrome (DS) can cause failure to thrive in pediatrics, which is mostly found in optic pathway gliomas (OPGs) patients. OPGs patients with DS always show a poor outcome. Case presentation: We present the case of an OPG patient with DS who got a spontaneous regression without any treatment. A 6-month-old girl presented with failure to thrive for two months and visual dysfunction with bilateral horizontal nystagmus. MRI demonstrated a 42mm*37mm*36mm enhanced and lobulated lesion located in the sellar region with a clear boundary with surrounding tissues. OPG and DS was diagnosed according to her radiological examination and manifestation. Conservative follow-up was given. There was a spontaneous decrease in tumor size during follow-up. Symptom improves and the patient continues to have a good quality of life despite a moderate dysfunction of her left eye.Conclusions: Conservative observation can be used as a treatment for some OPG patients, body weight may be a marker of the growth of tumor in OPG patients with DS.

BT-4 The treatment history of long-term survivors of Optic Pathway Glioma in Kobe Children’s Hospital

Optic pathway glioma(OPG) is almost recognized in childhood and about 0.01–0.02% of whole brain tumor in Japan. Because of the rare tumor, there are few reports about results of its treatment. In 2021, Guideline of Optic pathway/hypothalamic glioma is indicated from The japan Society for Neuro-Oncology. We retrospectively study 9 cases history of OPG who have treated for more than 5 years from January 2005 to March 2021 in Kobe Children’s Hospital. Cases are 4 boys and 5 girls. Average age at diagnosis is 3.8 years old and average follow up term is 11 years 10 months. They are 4 Pilocytic astrocytoma, 3 Pilomyxoid astrocytoma, and 1 Fibrillary astrocytoma. Al l cases have survived. There are only 2 cases who could be controlled with single series of surgical treatment and chemotherapy. Most cases need several times of resection and chemotherapy and uncontrollable 5 cases required radiological treatment. 2 cases are still under treatment for over 10 years. For OPG, partial resection to control hydrocephalus is recommended and several trial of chemotherapy must be carried out. There exist a few cases who need continuous treatment for long term. The other side, a few cases are uncontrollable those need radiotherapy to manage tumor volume. Because the history of OPG would be long term, we should adjust the treatment plan to environment of patients.

Optic pathway glioma and the sex association in neurofibromatosis type 1: a single-center study

Background Low-grade optic pathway glioma (OPG) develops in 15–20% of children with neurofibromatosis type 1 (NF1). OPGs are symptomatic in 30–50% and one-third of these require treatment. A few studies have suggested female sex as a risk factor for visual impairment associated with NF1-OPG. This descriptive study investigated the correlation between NF1-OPG growth, sex and visual impairment. Method We based our cross-sectional study on a systematic, retrospective data collection in a NF1 cohort of children and adolescents below 21 years of age followed at Center for Rare Diseases, Aarhus University Hospital, Denmark. For each patient with OPG a medical chart review was performed including demographics, ophthalmological examinations and magnetic resonance imaging (MRI) of OPG. Results Of 176 patients with NF1 (85 females, 91 males), we identified 21 patients with OPG (11.9%) with a preponderance of females, p = 0.184. Eight females (62%) and one male (13%) had visual impairment at the last ophthalmological evaluation. Five out of 21 children with OPG (24%) underwent diagnostic MRI because of clinical findings at the ophthalmological screening. Nine children (43%) had symptoms suggestive of OPG and seven (33%) experienced no OPG-related symptoms before the diagnostic MRI. Of eight children diagnosed with OPG ≤ two years of age, one had visual impairment. Of 13 children diagnosed > two years of age, eight had visual impairment; in each group, four of the children were treated with chemotherapy. The study suggested no correlation between NF1-OPG growth and sex. Conclusion Our data suggest sex as a risk factor for visual impairment, while an OPG diagnose ≤ two years of age was a protective factor for visual impairment. Females with NF1-OPG had a higher prevalence of visual impairment outcome compared to males. Interestingly, our data also suggest a better response to treatment in children with OPG diagnosed ≤ two years of age compared to older children. The findings in our study suggest sex as a potential prognostic factor for visual impairment.

NCOG-22. RETROSPECTIVE ANALYSIS OF VISUAL OUTCOMES AFTER BEVACIZUMAB-BASED THERAPY IN OPTIC PATHWAY GLIOMA

BACKGROUND Patients with optic pathway glioma (OPG) are vulnerable to debilitating visual impairment. Consequently, vision stabilization is a primary treatment goal. Bevacizumab has demonstrated promising effects on radiographic tumor burden, but less is known about its impact on vision. Our objective was to characterize visual outcomes associated with bevacizumab-based therapy (BBT) in OPG. METHODS This is a single-institution, retrospective review of patients treated with BBT for OPG from 2011 to 2020. Ophthalmologic and radiographic data were abstracted before and after treatment. Clinically significant visual acuity (VA) impairment was defined as logMAR &gt; 0.5 and change in VA was defined as change from baseline of logMAR ≥ 0.2. RESULTS Sixteen patients (13 sporadic OPG, 3 NF1-associated OPG) with evaluable vision outcomes were identified. Treatment indications were radiographic progression (N=15) and vision deterioration (N=4). Prior to BBT, 15 (94%) had failed at least one chemotherapy regimen. BBT regimens included bevacizumab/irinotecan (N=12), bevacizumab monotherapy (N=3) and bevacizumab/vinblastine (N=1). Nine patients (56%) had baseline VA impairment. Thirteen patients (81%) had stable or improved vision after BBT, including 8 of 9 with baseline VA impairment and all 4 patients with vision deterioration as a treatment indication. Eleven patients (69%) had radiographic progression following BBT (Median time-to-progression 66 weeks, IQR 27 weeks), 9 of whom had stable vision at time of progression. There were no associations between VA and age at treatment, NF1-status, histology, or BBT regimen. CONCLUSIONS BBT was associated with favorable visual outcomes for most patients with OPG in this modest retrospective cohort. Consistent with prior research, radiographic and ophthalmologic outcomes were discordant; a majority of patients experienced progressive disease despite stable vision. Next steps include (1) assessing visual field and optical coherence tomography outcomes in the same cohort and (2) comparing outcomes for BBT with other common therapies including carboplatin/vincristine and vinblastine.

TAMI-69. NF1 MUTATION DRIVES NEURONAL ACTIVITY-DEPENDENT OPTIC GLIOMA INITIATION

Neurons have recently emerged as essential cellular constituents of the tumor microenvironment, where their activity increases the growth of a diverse number of solid tumors. While the role of neurons in tumor progression has been previously demonstrated, the importance of neuronal activity to tumor initiation is less clear, particularly in the setting of cancer predisposition syndromes. In the Neurofibromatosis-1 (NF1) cancer predisposition syndrome, in which tumors arise in close association with nerves, 15% of individuals develop low-grade neoplasms of the optic pathway (optic pathway gliomas [OPGs]), during early childhood, raising the intriguing possibility that postnatal light-induced optic nerve activity drives tumor initiation. Here, we employ an authenticated murine model of Nf1-OPG to demonstrate that stimulation of optic nerve activity increases optic glioma growth, while decreasing visual experience via light deprivation prevents tumor formation and maintenance. We show that Nf1-OPG initiation depends on visual experience during a developmental period susceptible to tumorigenesis. Germline Nf1 mutation in retinal neurons results in aberrantly high optic nerve neuroligin-3 (Nlgn3) shedding in response to retinal neuronal activity. Moreover, genetic Nlgn3 loss or pharmacological inhibition of Nlgn3 shedding blocks murine Nf1 optic gliomagenesis and progression. Collectively, these studies establish an obligate role for neuronal activity in the development of certain brain tumors, elucidate a therapeutic strategy to reduce OPG incidence or mitigate tumor progression, and underscore the role of Nf1 mutation-mediated dysregulation of neuronal signaling pathways in the NF1 cancer predisposition syndrome.