As reported on Inside Precision Medicine, researchers at Stanford Medicine and the VA Palo Alto Health Care System have created a new urine test called uRARE-seq that could change how bladder cancer is detected and treated.
Instead of searching for mutated DNA like many traditional liquid biopsy tests, uRARE-seq measures cell-free RNA (cfRNA)—fragments of genetic code released into urine that show which genes cells are actively using. This gives doctors a real-time window into active tumor behavior in addition to revealing if cancer is present.
While urine tests for bladder cancer already exist (such as NMP22, UroVysion, or Xpert Bladder Cancer Monitor), uRARE-seq tracks gene expression on a much broader scale. The researchers noted that “a key distinguishing feature of cfRNA compared to utDNA approaches is the ability to profile the expression of thousands of genes,” using a panel of 381 genes for their detection model.
In a trial analyzing 683 urine samples published in Nature Medicine, uRARE-seq yielded several major findings:
- High Accuracy: It detected 95% of localized bladder cancers with 90% specificity (meaning low false-positive rates).
- Bypasses False Flags: It was unaffected by the “field effect”—a common issue in urine DNA testing where normal, healthy bladder lining cells accumulate mutations that mimic tumors.
- No Pre-Tissue Sequencing Required: It outperformed conventional urine cytology and performed on par with custom “tumor-informed” DNA tests, but without requiring doctors to biopsy and sequence a patient’s tumor first.
- Predicts Treatment Success: By examining pre-treatment urine samples from 114 patients, researchers created a model to predict whether a patient would respond better to intravesical Bacillus Calmette-Guérin (BCG) immunotherapy or chemotherapy, scoring a 0.93 out of 1.0 in predictive accuracy.
- Tracks Residual Disease: It reliably detected lingering microscopic cancer cells following surgery or initial treatment.
Why This Is Good News for High-Risk Patients
For individuals at higher risk of developing or experiencing a recurrence of bladder cancer, this test offers three key advantages:
- Fewer Invasive Procedures: Today, diagnosing and monitoring bladder cancer frequently requires cystoscopy—a procedure where a camera tube is inserted through the urethra into the bladder. A non-invasive urine test that catches 95% of localized cancers could reduce the need for frequent, uncomfortable scope exams.
- Right Treatment from Day One: Bladder cancer treatments like BCG immunotherapy can cause painful side effects and don’t work for every patient. Because uRARE-seq reads gene expression patterns, it helps doctors predict before treatment begins whether BCG or chemotherapy offers the highest chance of success, saving critical time.
- Early Catch of Recurrences: Bladder cancer has one of the highest recurrence rates of any cancer. By detecting tiny amounts of remaining cancer (molecular residual disease) after surgery, doctors can intervene earlier before a tumor regrows or spreads.
Key Bladder Cancer Statistics
- Annual Cases (U.S.): Approximately 84,530 new cases of bladder cancer are diagnosed in the United States each year (about 64,730 in men and 19,800 in women).
- Annual Deaths (U.S.): It accounts for roughly 17,870 deaths annually.
- Gender Disparity: Men are about 3 to 4 times more likely to develop bladder cancer than women.
- High Recurrence Rate: Approximately 50% to 70% of non-muscle-invasive bladder tumors recur after initial treatment, making continuous lifelong monitoring necessary.
5-Year Survival: The overall 5-year relative survival rate is approximately 79%, but drops significantly if the cancer spreads beyond the bladder before detection.
