ID #1078 FGFR Alterations are Associated with Reduced Extent of Resection in Pediatric Low-Grade Gliomas
Dylan Keusch, Carolina Lopes, Casey Jarvis, Susan Chi, Karen Wright, Tom Rosenberg, Nicole Ullrich, Kee Kiat Yeo, Hart Lidov, Sanda Alexandrescu, Mariella Filbin, Pratiti Bandopadhayay, Katie Fehnel, Lissa BairdAbstract
Introduction
Low-grade gliomas (LGGs) are the most common central nervous system tumors in children and are most frequently driven by alterations in the RAS/MAPK signaling pathway.1-3 Fibroblast growth factor receptor (FGFR) alterations define a distinct molecular subgroup that is well characterized genomically but poorly described from a surgical perspective. Given the association between extent of resection and recurrence risk in LGG, we aimed to compare surgical outcomes between FGFR-altered and FGFR wild-type (WT) tumors.
Methods
We conducted a single-center retrospective cohort study of patients <21 years of age who underwent resection of a low-grade glioma between 1989 and 2024. Clinical, pathologic, molecular, and surgical variables were analyzed. Statistical analyses were performed in R (v4.2.2) using descriptive statistics, chi-square or Fisher’s exact tests for categorical variables, and logistic regression for repeat surgery outcomes.
Results
A total of 569 pLGG were included, comprising 66 tumors harboring FGFR alterations and 503 FGFR WT tumors. FGFR-altered tumors presented at an older median age than WT tumors (12.4 vs. 9.3 years, p = 0.023), with similar sex distribution (p = 0.60). FGFR-altered tumors were more often WHO grade II (59.1% vs. 15.1%, p < 0.001) and supratentorial (77.3% vs. 51.5%, p < 0.001). FGFR-alteration was associated with lower rates of gross total resection at index surgery (28.8% vs. 44.5%, p < 0.023) and a higher likelihood of repeat resection (34.8% vs. 20.5%; OR 2.07, 95% CI 1.14-3.70; p = 0.011).
Conclusions
FGFR-altered pediatric low-grade gliomas are associated with lower rates of gross total resection and increased need for repeat surgery compared with FGFR WT tumors. This likely reflects a propensity for these tumors to infiltrate eloquent or surgically high-risk brain structures, which constrains the extent of safe resection and emphasizes the importance of targeted strategies for residual disease.