Therapeutic and Prognostic Implications of the BRAF V600E in Pediatric Low-Grade Gliomas
Pediatric low-grade gliomas (PLGGs) are a heterogeneous group of tumours. BRAF V600E-mutatant PLGGs are thought to represent a unique, more aggressive subtype, however this is controversial. BRAF V600E is a potentially targetable mutation.
Retrospective study. Genetic, clinical, treatment, and outcome data from an unselected group of patients with PLGGs from a single centre database (Toronto, n=405) compared to outcomes from an independent cohort of patients with BRAF V600E-mutated PLGG from 18 collaborating international pediatric centres (n= 180).
BRAF V600E mutation was detected in 17% patients with PLGG in the Toronto cohort and these patients had worse outcome compared to wild-type PLGGs with 10-year PFS 27% vs 60% and OS 84% vs 92%. PFS and OS were similar when compared to independent cohort outcomes. Multivariate analysis identified that patients with BRAF V600E mutation, CDKN2A deletion and incomplete resection had the worst prognosis. Six patients treated with BRAF inhibitor after progression with conventional therapy had significant response, median follow up 18.5 months.
Single centre study but compared outcomes to smaller international cohort which demonstrates similar outcomes. Too few patients from one centre to truly understand the role of BRAF inhibitors in this patient population.