ID #348 Balancing cure and survivorship in pediatric low-grade glioma using a radiation-sparing approach: an experience from India

Abstract Background With excellent long-term survival, contemporary treatment of pediatric low-grade glioma (pLGG) focuses on minimizing late toxicities and improving quality of life. Neuroradiation is associated with significant long-term sequelae, particularly in younger children. We evaluated the feasibility of chemotherapy as a radiation-sparing or delaying strategy in pLGG. Material and Methods Children 18 years with radiologically or histologically confirmed pLGG treated between January 2011 and December 2022 were included. Management comprised surgery where feasible, observation following gross resection or favorable biology, and systemic therapy after multidisciplinary discussion ( vincristine–carboplatin first-line, vinblastine monotherapy second-line or in neurofibromatosis (NF)-pLGG, and trametinib in recent years). Radiotherapy (RT) was avoided or delayed whenever possible and generally administered after failure of two systemic lines or symptomatic progression. Progression-free survival (PFS), radiation-free survival (RaFS), and overall survival (OS) were estimated using Kaplan–Meier methods. Results In 423 patients, median age at diagnosis was 8 years; 10.6% had NF. Common sites included cerebellum (26%), optic pathway hypothalamic (33.5%), cerebral hemispheres (18.7%), and brainstem (6.4%). At a median follow-up of 70 months, 413 patients received first-line therapy; 139 second-line, 23 third-line and 5 fourth-line. 140 (31.7%) ultimately received RT; median age at RT was 11years, and median time to RT 24months. 6-year PFS was 61.9%, RaFS 70.2%, and OS 90.2%. RaFS was 72% in BRAF fusion (n = 77) and 43% in BRAF-v600E mutant (n = 31), p = 0.01, and median RaFS was 77months and 31months respectively. Patients with NF (n = 42) had higher PFS (83.2% vs 59.7%, p = 0.1). Endocrine dysfunction was more frequent after RT (21.6% vs 7.2%, p 0.001). One patient each had high-grade transformation, Moya moya disease and cavernoma. Conclusion RT could be avoided in a substantial proportion of children, especially BRAF- fusion, and delayed in others, resulting in fewer late toxicities. A radiation-sparing approach is feasible across settings with careful multidisciplinary decision-making.