Molecular subtyping of metastatic urothelial bladder cancer.

Abstract

326 Background: TCGA molecular sybtyping is established in metastatic urothelial bladder cancer (UBC). It remains unclear if it is of prognostic importance with chemotherapy in metastatic UBC. Data into immune therapy suggests TCGA subtyping is predictive to response. Methods: Archival formalin-fixed paraffin embedded (FFPE) tissue were analysed from 170 patients that had consented into a clinical trial (NCT00949455) after first line chemotherapy for metastatic disease. Gene expression levels were quantified by NanoString technology. Molecular subtypes were assigned according to The Cancer Genome Atlas (TCGA) subtypes. Clinical information was available for all patients and analysis on individual genes were explored. Results: 170 patients were analysed, 75% male. 107 (64%) patients received cisplatin based first-line chemotherapy, with 36% receiving carboplatin based regimen. Median overall survival (OS) was 15.73 months [95% CI: 13.87-17.58], and median progression free survival (PFS) was 10.71 months [95% CI: 8.97-12.45]. Samples were initially clustered into luminal (n=109) and basal (n=61) subtypes. Response to first line chemotherapy occurred in all subtypes but was shown to be significantly higher in the luminal subtype versus the basal subtype [58% vs 20%, p=0.01]. PFS was superior in luminal subtypes [11.8 months vs 8.9 months, p=0.005]. Exploratory analysis showed that luminal II subtype had the best outcome for OS [20.3 months, p=0.03] compared to the other subtypes. Outcomes with other genes including immune markers were explored. TCGA outcomes can be summarised in the table. Conclusions: In metastatic urothelial cancer, TCGA subclassifying influences outcome of patients post chemotherapy. [Table: see text]