A breakthrough urine-based DNA test could revolutionize personalized care for bladder cancer patients by predicting which individuals are most likely to experience cancer recurrence after immunotherapy treatment, according to a multi-institutional study published in Science Direct.
The research analyzed urine-based tumor DNA (utDNA) from patients enrolled in the SWOG S1605 trial who received atezolizumab, an immunotherapy drug. Using the UroAmp test, researchers examined urine samples from 89 patients at treatment initiation and 77 patients three months later to determine whether utDNA could identify patients most likely to respond to immunotherapy.
Clinical Trial Design and Methodology
The SWOG S1605 study was a phase 2 clinical trial testing atezolizumab in patients with high-risk bladder cancer that failed to respond to BCG (Bacillus Calmette-Guérin) treatment, the standard immunotherapy for early-stage bladder cancer. Samples were collected from participants before treatment and again three months later.
Researchers employed the UroAmp assay, a non-invasive urine test that detects bladder cancer-related mutations, to analyze utDNA and generate genomic profiles for each patient. The study aimed to establish correlations between utDNA levels and treatment outcomes.
Key Findings and Clinical Implications
The study revealed that utDNA levels were significantly linked to patient response rates after six months and duration of cancer-free survival over 18 months. Patients with positive utDNA results demonstrated lower response rates and higher likelihood of cancer recurrence compared to those with negative results.
"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. "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."
Disease Burden and Treatment Challenges
According to the American Cancer Society, bladder cancer ranks as the sixth most common cancer in the United States, with more than 83,000 new cases diagnosed annually. Approximately 75% of these cases are non-muscle invasive, meaning the cancer has not yet invaded the bladder muscle.
Patients who fail to respond to immunotherapy face difficult treatment decisions, including continuing bladder-sparing therapies with high recurrence risks or undergoing major surgery that removes the bladder and significantly impacts quality of life.
Potential for Personalized Medicine
This study offers new hope for patients with high-risk bladder cancer by demonstrating that urine-based DNA testing can predict immunotherapy benefit. By enabling early identification of treatment response, this approach could guide more personalized, bladder-preserving care and reduce the need for major surgical interventions.
The research was conducted through SWOG, also known as Southwest Oncology Group, which is part of the National Cancer Institute's National Clinical Trials Network and represents one of the five leading cancer clinical trial groups in the United States.
