Neurotrophic tropomyosin receptor kinase (NTRK) fusion positive tumors: a historical cohort analysis

NTRK gene fusions have been identified in various tumors; some requiring aggressive therapy and sometimes new TRK inhibitors (TRKi). We aimed to describe a national, unselected, retrospective, multicenter cohort. Patients were identified through the French sarcoma diagnostic laboratory at Institut Curie through samples analyzed by RT-qPCR or whole-transcriptome sequencing. From 2001 to 2019, 65 NTRK fusion tumors were identified within 2120 analyses (3.1%): 58 by RNA sequencing (including 20 after RT-qPCR analysis) and 7 exclusively by RT-qPCR. Of the 61 patients identified, 37 patients had infantile soft tissue or kidney fibrosarcomas (IFS), 15 other mesenchymal (Other-MT) and nine central nervous system (CNS) tumors. They encompassed 14 different tumor types with variable behaviors. Overall, 53 patients had surgery (3 mutilating), 38 chemotherapy (20 alkylating agents/anthracycline), 11 radiotherapy, two ‘observation strategy’ and 13 received TRKi. After a median follow-up of 61.0 months [range, 2.5–226.0], 10 patients died. Five-year overall survival is, respectively, 91.9% [95%CI, 83.5–100.0], 61.1% [95%CI, 34.2–100.0] and 64.8% [95%CI, 39.3–100.0] for IFS, Other-MT, and CNS groups. NTRK-fusion positive tumors are rare but detection is improved through RNA sequencing. TRKi could be considered at diagnosis for CNS NTRK-fusion positive tumors, some IFS, and Other-MT. Not adapted.