Optic pathway gliomas in children: Demographic, clinical characteristics, and results of an adapted protocol.

Abstract

e22016 Background: Optic pathway gliomas (OPG) constitute 1-5% of childhood brain tumors. The presence of neurofibromatosis type 1 (NF-1) is generally associated with more indolent disease. The aim of this study is to evaluate patients with optic pathway gliomas diagnosed/treated/ followed in a single center over 32 years. Methods: The medical files of 85 patients with OPG diagnosed/treated between 1990-2021 in the Istanbul University, Oncology Institute were retrospectively assessed for demographic, clinical characteristics, treatment and outcome. Results: The median age of the 85 patients (42 male, 43 female) was 60 (1-216) months, 53 (62.4%) had NF-1. Seven had diencephalic syndrome (8.2%). According to Dodge classification, 23 (27.1%) had Dodge 1, 30 (35.3%) Dodge 2 and 32 (37.6%) Dodge 3 disease. Median follow up time was 10.5 years (1-31 years). Twenty (23.5%) patients had stable disease and were followed without treatment, 14 patients underwent surgery (5 gross total tumor resection, 2 subtotal resection, 3 ventriculoperitoneal shunt operation, 4 excision/biopsy). 7 patients recieved radiotherapy (RT), none had NF1. 56 patients received chemotherapy (CT) due to severe/progressive clinical symptoms (such as diencephalic syndrome, visual impairment, nystagmus) or radiologic progressive disease. Chemotherapy consisted of an adapted SIOP-LGG regimen: vincristine (VCR) 1.5 mg/m²/dose and carboplatinum 550 mg/m²/dose every 21 days for three courses with weekly VCR, followed by VCR and carboplatinum every 28 days for a total of 12 cycles (3 cycles induction, 9 cycles consolidation). Vinblastin or cisplatinum with etoposide were used for second line or further treatment in progressive disease. One of the seven patients who had diencephalic syndrome and two of the 3 patients with leptomeningeal metastasis died. Ocular findings were recorded in 47 patients: vision was stable in 30 (63.8%), improved in 15 (31.9%), detoriated in 2 (4.3%). Radiology (MRI) revealed stable disease/regression of tumor in 41 patients, and complete regression of spinal metastasis in 1 patient. Endocrinologic follow-up was done and 13(15.2%) recieved hormonal treatment. Ten year overall survival(S) in all patients, in patients with NF1 and without NF1 were 96.5%, 96.1% and 95%, respectively; 10 year event free survival (EFS) in all patients, in patients with NF1 and without NF1 were 80.6%, 90.5% and 60% (p:0.001) respectively. Conclusions: OPG may remain indolent for many years after diagnosis, especially in patients with NF 1. However, these tumors develop progressive characteristics and can cause visual disturbances, endocrine dysfunction, blindness and even death among some of the patients. In young children who are symptomatic/have progressive disease, chemotherapy with an adapted regimen consisting of vincristine and carboplatinum seems to be effective and provides a relatively good quality of life.