Circulating tumor DNA as a prognostic and monitoring biomarker in urothelial cancers.

The application of circulating tumor DNA (ctDNA) has advanced in the treatment of multiple cancer types, including urothelial cancer (UC). While ctDNA currently plays a limited role in non-muscle-invasive bladder cancer (NMIBC), its relevance is expanding in muscle-invasive bladder cancer (MIBC), as evidenced by recent positive results from the IMvigor011 trial. This study demonstrated that a ctDNA-guided approach to adjuvant atezolizumab therapy enhances disease-free survival. Furthermore, ctDNA is well-established as a tool for monitoring treatment response and assessing minimal residual disease (MRD) in metastatic urothelial cancer (mUC). This narrative review explores the current data on the clinical utility of ctDNA in various disease states within UC to help guide clinicians in the appropriate setting and application of ctDNA based on retrospective, current, and emerging data.