Integrating clinically actionable biomarkers into bladder cancer care - recommendations from the International Bladder Cancer Group.

Crucial unmet needs for standardization and clinical integration of actionable biomarkers persist across the bladder cancer disease spectrum. To address these gaps, the International Bladder Cancer Group (IBCG) convened a global multidisciplinary panel to develop evidence-based consensus recommendations on biomarker use in bladder cancer. Recommendations were formulated across the disease spectrum using a modified Delphi process. In patients with asymptomatic microhaematuria, biomarker use should be guided by a risk-stratified approach. For patients with established non-muscle-invasive bladder cancer, no biomarker prospectively validated is available to guide intravesical therapy selection, although approved commercial tests might aid in adjudicating equivocal cytology or cystoscopy findings in patients with high-grade disease. In muscle-invasive bladder cancer, no validated biomarkers exist to guide the choice between bladder preservation and radical cystectomy, or to inform the choice of neoadjuvant therapy. Circulating tumour DNA is prognostic following neoadjuvant therapy and radical cystectomy, and provides predictive value for selecting patients who are most likely to benefit from adjuvant treatment with approved immunotherapy regimens. In addition, circulating tumour DNA has prognostic value in patients with metastatic urothelial carcinoma. The IBCG recommends assessing FGFR3 genomic alterations and HER2 immunohistochemistry in patients with locally advanced and/or metastatic bladder cancer to inform therapeutic selection. The IBCG consensus recommendations provide practical, stage-specific guidance on the use of biomarkers for diagnosis, risk stratification and treatment selection in patients with bladder cancer and define priorities for future validation and trial design.