IBCN 2023: A Composite Biomarker Approach to Spare Neoadjuvant Chemotherapy in Select Muscle-Invasive Bladder Cancer Patients

Clinical guidelines recommend neoadjuvant chemotherapy (NAC) prior to radical cystectomy (RC) for the management of muscle-invasive bladder cancer (MIBC), despite treatment-related toxicity and a modest survival benefit. Here, they identified MIBC patients who may avoid NAC using a composite biomarker approach of circulating tumor cell status and molecular subtypes.

Trans urethral resection of bladder tumor (TURBT) samples were collected from clinical stage T2-T4aN0-N1M0 cases included in the prospective CirGuidance study (NL3954) that analyzed circulating tumor cell (CTC) status in patient blood using the CELLSEARCH system. For the present study, transcriptome-wide expression profiling was performed on 234 TURBT samples using an array-based approach. Molecular subtypes, long non-coding RNA (lncRNA) based FGFR3+ status, and gene signatures were determined as described previously (PMID 31619281). The primary endpoint of this study was cancer-specific mortality (CSM), calculated as the date of study inclusion till date of bladder cancer related death. Median follow-up was 28.8 (IQR:16.6-40.2) months.

Of 234 patients, 21 (9%) were treated with NAC and RC, while 213 (91%) received RC alone. A CTC-negative status was observed in 172 (81%) of RC-only cases. Molecular subtyping identified 28 luminal FGFR3+ cases with high FGFR3, SHH, and p53 pathway
activity, and lower EMT hallmark scores. Adjusting for clinical risk factors, both CTC and FGFR3+ status were significant predictors for cancer specific mortality on MVA (P<0.05). Of interest, the subgroup of FGFR3+ cases that were CTC-negative (N=26) showed most favorable outcomes with only one CSM event after a median of 33.4 (IQR: 24.8-44.5) months of follow-up.

Using a composite biomarker approach of blood-based CTC status and molecular subtyping, we identified a biologically distinct subgroup of MIBC with favorable prognosis after RC-only, validating the performance of a previously developed lncRNA based FGFR3+ classifier. Clinical trials which withhold NAC from CTC-negative, FGFR3+ MIBC patients are warranted.

Presented by: Joep J. de Jong, Erasmus University Medical Center & Franciscus Hospital, Rotterdam, The Netherlands

Written by: Stephen B. Williams, MD, MBA, MS @SWilliams_MD on Twitter during the International Bladder Cancer Network (IBCN) Annual Meeting, September 29-30, 2023, Montreal, Canada