Background: Recent targeted therapies for advanced and metastatic urothelial cancer have generated enthusiasm, but the actionable genomic landscape of early-stage disease remains largely unknown. Here, we utilized a large, real-world cohort to comprehensively investigate the incidence of genetic alterations with potential therapeutic implications at all stages of bladder cancer.
Materials and methods: We retrospectively analyzed next-generation sequencing (NGS) data from 1,562 bladder cancer patients (stages I-IV) with formalin-fixed, paraffin-embedded tumor biopsies sequenced using the Tempus xT solid tumor assay. Incidence of genetic alterations, tumor mutational burden (TMB), microsatellite instability (MSI), and PD-L1 status were assessed and stratified by bladder cancer stage. For patients with tumor-normal match sequencing (n=966), incidental germline alterations in 50 genes were assessed.
Results: The cohort was composed of 165 stage I-II, 211 stage III, and 1,186 stage IV tumors. TMB-high, PD-L1 positive, and MSI-high status were noted in 14%, 33%, and 0.7% of tumors, respectively, and were similar across stages. Alterations in fibroblast growth factor receptor (FGFR)2/3, homologous recombination repair genes, additional DNA repair gene mutations (ERCC2, RB1, FANCC), and NTRK fusions were detected at similar frequencies across disease stages. We identified a low rate of incidental germline mutations in all tumors (5.2%) and in specific genes: MUTYH (1.9%), BRCA2 (0.5%), and ATM (0.8%).
Conclusions: Important subsets of patients demonstrate genetic alterations in potentially actionable molecular pathways at all stages. This analysis found minimal variability in these alterations across stages, providing rationale for early identification of genetic alterations and personalization of therapies at all stages for patients with bladder cancer.
Keywords: Actionable genetic target; Bladder cancer; Germline mutation; Somatic mutation; Urothelial carcinoma.
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