Background: The ESMO ESCAT scale rank molecular alterations (MA) based on the published evidence supporting their clinical use. Building on our proposal for the first ESCAT classification for primary brain tumors (pBT) [Mirallas et al. ESMO 2022], we aim to describe the clinical actionability of NGS in a multicentric glioma cohort and gather clinical factors that enrich patients with MA to justify performing NGS. Methods: A multicentric retrospective study included pts with molecular profiling using NGS methods (Foundation Medicine, local NGS, Caris, Oncomine,and fusion panels). Clinical actionability was classified using the ESCAT scale; Tier 1 (ready for clinical implementation), Tier 2 (alteration-drug match with antitumor activity), Tier 3 (supported in other tumor types), and Tier 4 (preclinical evidence). Clinical factors considered for enrichment were diagnosis of glioblastoma (GBM), sex, and age ≤40 years, differences between groups were determined using Chi-squared test. The overall survival (OS) was calculated through Kaplan-Meier method and cox hazard ratio were fitted. Results: A total of 361 pts with NGS performed between Feb 2018 and Dec 2022 at 4 hospitals in Spain. Median age was 51.5 (range, 3.3-83.8), 77% had ECOG ≥1, 39.2% were women, 23.4% were 40 or younger, 20.8% had IDH1mut, and 73.5% had a diagnosis of GBM. The distribution of MA according to ESCAT was: 10 pts ESCAT 1 (5 BRAFV600E mut, 5 NTRK 1-3 fusions); 75 pts ESCAT 2 (67 IDH1 mut, 6 FGFR-TACC rearrangement, 4 FGFR 1-3 mut, 3 IDH2 mut); 105 pts ESCAT 3 (98 PIK3CA/PTEN mut, 12 PTEN loss, 11 H3K27M mut, 6 BRAF fusion, 2 MET mut, 1 FGFR3 amplification); 93 pts ESCAT 4 (119 TERT mut, 77 EGFR gain, 67 CDKN2A loss, 58 CDKN2B loss, 48 EGFRvIII rearrangement, 46 ATRX mut, 40 EGFR mut, 8 ATM mut). Prevalence of Tier 1-2 MA was 23.6%. In relation to enrichment factors: 12% >40y pts had ESCAT1-2 vs 61% in ≤40y (p<0.001), pts with GBM had a 11% prevalence vs 61% non-GBM (p<0.001), and non-gender differences were seen. The median OS for Tier 1-2 was 135 months (95% CI 166-99) vs Tier 3-4 of 24 months (95% CI 21.5-29.6). Significantly worse OS was observed for Tier 3-4 gliomas (HR: 4.11; 2.84-5.95, p<0.001), and remained significant after adjusting for histology and hospital center (p<0.01). Conclusions: The prevalence of ESCAT Tier 1-2 alterations is high in gliomas suggesting that molecular profiling should be offered, at least, in tertiary centers where these techniques are available. Potential enrichment factors to offer NGS were age and non-GBM pBT, but not gender.