Monitoring tumor-derived DNA in blood and urine can identify patients with muscle-invasive bladder cancer who are most likely to remain cancer-free after treatment without undergoing bladder removal.
In a study published in Proceedings of the National Academy of Sciences, investigators evaluated circulating tumor DNA (ctDNA) in plasma and urine tumor DNA (utDNA) in patients enrolled in a clinical trial of a bladder-sparing strategy. Participants who achieved a complete clinical response after tumor resection and systemic therapy were allowed to forgo immediate radical cystectomy, a life-altering procedure that permanently changes urinary function.
Three-year bladder-intact survival among patients with a complete clinical response was 69 percent, supporting the durability of bladder preservation in selected individuals. Detectable ctDNA before systemic therapy was associated with a higher likelihood of developing metastatic disease, whereas patients with undetectable baseline ctDNA had a lower risk.
utDNA was more sensitive than ctDNA for detecting residual disease confined to the bladder. Detectable utDNA in patients who otherwise appeared to have no evidence of cancer was associated with shorter bladder-intact survival, suggesting that urine-based assays may uncover occult disease not visible on imaging or biopsy.
The findings establish a foundation for integrating liquid biopsy assays into routine management of muscle-invasive bladder cancer. Lead researcher Matthew Galsky, Deputy Director of the Mount Sinai Tisch Cancer Center, said, “These findings show that blood and urine DNA testing provide complementary information. Together, they offer a powerful new way to identify patients most likely to benefit from bladder preservation.”
Ongoing studies are aimed at validating the approach in larger cohorts.
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