Urine-Based DNA Test Helps Tailor Cancer Therapy

In a multi-institutional study published in Science Direct, researchers revealed that testing urine-based tumor DNA (utDNA) can help predict which bladder cancer patients are at higher risk for recurrence after treatment.

This study analyzed utDNA from patients in the SWOG S1605 trial, who were treated with atezolizumab, an immunotherapy drug. Researchers used the UroAmp test to examine urine samples from 89 patients at the start of treatment and from 77 patients three months later. The goal was to see if utDNA could help identify which bladder cancer patients are most likely to respond to immunotherapy.

 “This approach could help improve patient care by guiding more effective treatments and supporting more personalized plans,” said Robert Svatek, MD, MSCI, professor and chair of urology at the Joe R. and Teresa Lozano Long School of Medicine at The University of Texas Health Science Center at San Antonio (UT Health San Antonio). “It means we may be able to tailor therapy sooner, reduce unnecessary delays and help patients avoid major surgery without compromising the quality of their care.”

 A nationally recognized urologic oncologist with the Mays Cancer Center at UT Health San Antonio, Svatek is the leading expert in bladder cancer and a member of SWOG, also known as Southwest Oncology Group. SWOG is part of the National Cancer Institute’s (NCI) National Clinical Trials Network (NCTN) and one of the five leading cancer clinical trial groups in the United States.

The SWOG S1605 study was a phase 2 clinical trial testing atezolizumab in patients with high-risk bladder cancer that didn’t respond to BCG (Bacillus Calmette-Guérin) treatment, the main immunotherapy to treat early-stage bladder cancer.

 Samples were collected from participants before treatment and again three months later. Researchers used the UroAmp assay, a non-invasive urine test that detects bladder cancer–related mutations, to analyze utDNA and generate a genomic profile for each patient.

They found that utDNA levels were linked to how well patients responded after six months and how long they stayed cancer-free over 18 months. Patients with positive utDNA results were less likely to respond and more likely to have their cancer return.

According to the American Cancer Society, bladder cancer is the sixth most common cancer in the United States, with more than 83,000 new cases diagnosed annually. Of these cases, approximately 75% are non–muscle invasive, meaning the cancer has not yet invaded the bladder muscle.

Patients who don’t respond to immunotherapy may face the difficult decision of either continuing therapies that spare the bladder but carry high risks of recurrence or undergo major surgery that removes the bladder and profoundly impacts one’s quality of life.

This study offers new hope for patients with high-risk bladder cancer by showing that a urine-based DNA test can help predict who is more likely to benefit from immunotherapy. By identifying treatment response early, this approach could guide more personalized, bladder-preserving care and reduce the need for major surgery.

Reference: St-Laurent MP, Singh P, McConkey DJ, et al. Urine tumor DNA to stratify the risk of recurrence in patients treated with atezolizumab for bacillus Calmette-Guérin–unresponsive non-muscle-invasive bladder cancer. European Urology. 2025. doi: 10.1016/j.eururo.2025.03.023

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