Clinical characteristics and outcome of a large cohort of patients with primary central nervous system (CNS) tumors and tropomyosin receptor kinase (TRK) fusion.

Abstract

2052 Background: TRK fusions are detected in less than 3% of central nervous system (CNS) tumors. Given their rarity, there are limited data on the clinical course of affected patients. Methods: We contacted 166 oncology centers worldwide to retrieve data on patients with TRK fusion-driven CNS tumors. Data extracted included demographics, histopathology, TRK gene fusion, treatment modalities and outcomes. Results: Ninety-two patients with TRK fusion-driven primary CNS tumors were identified including 76 pediatric patients (82.6%), 15 adults (16.3%) and 1 not specified (1.1%). Median age at diagnosis was 4.4 years (range 0.0–78.3) and 58.7 % were male. NTRK2 gene fusions were found in 45 patients (48.9%), NTRK1 and NTRK3 aberrations were detected in 27 (29.3%) and 20 (21.7%), respectively. Tumor types included 56 high-grade gliomas (HGG; 60.9%), 20 low-grade gliomas (LGG; 21.7%), 4 embryonal tumors (4.3%) and 12 others (13.0%). Median follow-up was 40.5 months (range 3–226). During the course of their disease, 75 (81.5%) patients underwent surgery with a treatment intent, 67 (72.8%) patients received chemotherapy, 50 (54.3%) patients received radiation therapy, while 47 (51.1%) patients received NTRK inhibitors (6 as first line treatment). There were significant differences in the median progression-free (PFS) and overall survival (OS) between pediatric patients compared to adults. The pediatric median PFS was 32 months (95% CI: 15.5–48.5) compared to 8 months for the adult (95% CI: 4.5–11.5, p = 0.015). The pediatric median OS was 182 months (95% CI: 25.1–338.9) compared to 24 months (95% CI: 18.3–29.7 p < 0.001) for adult patients. There was no difference in the PFS of LGG compared to HGG. However, the OS was significantly worse for the HGG when compared to LGG (p = 0.039). The median OS for LGG was not reached and the median OS for HGG was 70 months (95% CI 7.5–132.5). Nineteen patients with HGG (38.0 % 19/50 evaluable patients) died compared to only one patient with LGG (5.6% 1/18 evaluable patients, p = 0.014). Conclusions: We report the largest cohort of patients with TRK fusion-driven primary CNS tumors. These results will help us to better understand clinical evolution and compare outcomes with ongoing clinical trials.