Real-World Clinical Utility of Tumor Next-Generation Sequencing in Adolescent and Young Adult Patients With Sarcoma.

Purpose: Tumor next-generation sequencing (NGS) enables molecular profiling to identify actionable mutations and guide targeted therapy. Adolescent and young adults (AYAs) with advanced sarcoma often face poor prognosis and limited systemic options. This study evaluated the clinical utility of tumor NGS in this population.

Materials and methods: A retrospective cohort study was conducted at Chris O'Brien Lifehouse, Sydney, including consecutive AYA patients with sarcoma who underwent tumor NGS between 2015 and 2025. Sequencing was performed through four molecular screening programs: Molecular Screening and Therapeutics, Cancer Screening Program, Personalized Rare and Infrequent Solid Malignancies, Zero Childhood Cancer Program, and commercial platform Foundation Medicine (FoundationOne CDx). Platforms used whole-genome sequencing, whole-exome sequencing, or targeted panels, assessing between 324 and 523 genes. Analyzed biomarkers included somatic mutations, gene fusions, tumor mutational burden (TMB), and microsatellite instability. Key end points included frequency of actionable mutations, treatment changes, and outcomes from NGS-guided therapies.

Results: NGS was successfully performed in 108 of 115 patients (94%). Actionable mutations were identified in 28 patients (24.4%), with molecular confirmation of diagnosis in four (3.5%). TMB was reported in 93 cases: 88 (94.6%) had low TMB (<10 mut/MB) and five (5.4%) had high TMB (≥10 mut/MB). Sixteen patients (14.8%) received NGS-directed therapy, mostly through clinical trials. Of them, 12 (75%) experienced disease progression, and only five (4.4%) derived clinical benefit (stable disease, partial response, or complete response). Among high TMB patients accessing immune checkpoint inhibitors, all but one progressed.

Conclusion: Although few AYA patients with sarcoma derived clinical benefit from NGS-directed therapy (<5%), NGS proved useful for diagnosis and trial access. The absence of routine RNA sequencing may have limited the detection of fusion-driven sarcomas. Future integration of broader molecular techniques and collaborative infrastructure is essential to fully realize the potential of NGS in rare and high-risk sarcomas.