ctDNA is not a simple positive/negative binary test. Like PSA in prostate cancer, the quantitative level of ctDNA correlates with patient outcomes. Higher levels indicate a worse prognosis and a faster time to relapse, allowing for more nuanced risk stratification beyond a simple presence or absence of the biomarker.

Data from trials like Niagara suggests a powerful new paradigm for assessing treatment success. Combining urine tumor DNA (uTDNA) for local disease and circulating tumor DNA (ctDNA) for systemic relapse offers a more dynamic view than traditional pathology and is poised to become the superior surrogate endpoint in bladder cancer trials.

Upcoming trials like RETAIN and IMVigor011 are using circulating tumor DNA (ctDNA) to guide complex treatment choices in muscle-invasive bladder cancer. This biomarker-driven approach aims to personalize therapy, potentially enabling bladder preservation for some patients and identifying others who need additional adjuvant treatment.

The future of bladder cancer surveillance may involve using two types of liquid biopsies in tandem. A patient who is utDNA-positive but ctDNA-negative likely has a local, primary bladder issue. Conversely, a utDNA-negative but ctDNA-positive result suggests the cancer has already spread systemically, providing crucial information for treatment planning.

Professor Powles predicts that urinary tumor DNA (utDNA) will become the key biomarker for detecting local relapse in bladder-sparing strategies. He notes that blood-based ctDNA is poor at identifying non-muscle invasive disease, creating a clear and necessary role for utDNA to assess local risk and guide interventions more accurately.

In bladder preservation strategies, circulating tumor DNA (ctDNA) from blood is poor at detecting non-muscle invasive local recurrences. This limitation makes urine tumor DNA (utDNA) a necessary future tool for monitoring patients under active surveillance, potentially replacing invasive cystoscopies.

A positive circulating tumor DNA (ctDNA) test in a patient with a known bladder tumor can be misinterpreted as metastatic disease. However, the local tumor itself sheds DNA. Resecting this tumor can clear the ctDNA signal, a critical nuance to prevent misdiagnosis and premature, aggressive systemic therapy.

Experts suggest urinary tumor DNA (utDNA) may better reflect local disease in the bladder, while circulating tumor DNA (ctDNA) indicates systemic disease. Using both tests in parallel could provide a more complete picture, with dual-negative results potentially becoming a key criterion for safely pursuing bladder-sparing approaches.

A positive ctDNA (blood) but negative utDNA (urine) test suggests systemic, metastatic disease. Conversely, a positive utDNA with negative ctDNA points to a tumor confined to the bladder. This integrated biomarker approach can help determine whether systemic therapy or local treatment like surgery is the priority.