Circulating Tumour DNA and Its Prognostic Role in Management of Muscle Invasive Bladder Cancer: A Narrative Review of the Literature.

Current management of non-metastatic muscle invasive bladder cancer (MIBC) includes radical cystectomy and cisplatin-based neoadjuvant chemotherapy (NAC), offers a 5-year survival rate of approximately 50% and is associated with significant toxicities. A growing body of evidence supports the role of liquid biopsies including circulating tumour DNA (ctDNA) as a prognostic and predictive marker that could stratify patients according to individualised risk of progression/recurrence. Detectable ctDNA levels prior to radical cystectomy have been shown to be correlated with higher risk of recurrence and worse overall prognosis after cystectomy. In addition, ctDNA status after NAC/neoadjuvant immunotherapy is predictive of the pathological response to these treatments, with persistently detectable ctDNA being associated with residual bladder tumour at cystectomy. Finally, detectable ctDNA levels post-cystectomy have been associated with disease relapse and worse disease-free (DFS) and overall survival (OS) and might identify a population with survival benefit from adjuvant immunotherapy.