Objective:

To evaluate the effectiveness of monitoring circulating tumor DNA (ctDNA) and urine tumor DNA (utDNA) in identifying muscle-invasive bladder cancer patients who can avoid bladder removal.

Key Findings:

• Three-year bladder-intact survival among patients with complete clinical response was 69%.
• Detectable ctDNA before systemic therapy indicated a higher likelihood of metastatic disease.
• Patients with undetectable baseline ctDNA had a lower risk of metastasis.
• utDNA was more sensitive than ctDNA for detecting residual disease confined to the bladder.
• Detectable utDNA in patients with no visible cancer was linked to shorter bladder-intact survival.

Interpretation:

The study supports the integration of liquid biopsy assays into the management of muscle-invasive bladder cancer, providing complementary information from blood and urine tests.

Limitations:

• The study's findings need validation in larger cohorts.

Conclusion:

Blood and urine DNA testing may significantly enhance the identification of patients suitable for bladder preservation strategies.