Circulating tumor DNA and urinary tumor DNA: useful biomarkers for bladder cancer detection.

Introduction: Bladder cancer (BC), a prevalent urinary system malignancy, presents challenges for early diagnosis because of its nonspecific symptoms and late-stage presentation, leading to poor prognosis. Liquid biopsy, particularly urine-based testing, has emerged as a promising noninvasive alternative to tissue biopsy for early cancer detection, monitoring, and treatment guidance. Urinary tumor DNA (utDNA) and circulating tumor DNA (ctDNA) are key biomarkers that offer direct, noninvasive access to urinary tract tumor genetic information.

Areas covered: This review explores key dimensions of ctDNA and utDNA in BC, including BC epidemiology and current diagnostic limitations; cfDNA detection technologies; applications, advantages, and roles of ctDNA and utDNA in recurrence monitoring, treatment response assessment, and prognostic stratification; and ongoing clinical trials.

Expert opinion: ctDNA and utDNA are transformative tools in BC management, offering real-time insights into tumor dynamics, treatment response, and prognosis. The short half-life of ctDNA enables rapid assessment of tumor burden changes, whereas the noninvasive collection of utDNA enhances patient compliance. Despite challenges such as low biomarker abundance in urine, heterogeneity, and standardization gaps, ongoing clinical trials have validated its clinical utility. Future integration of ctDNA/utDNA into clinical practice will enable personalized, noninvasive BC care, improving early diagnosis, treatment optimization, and patient outcomes.