an international team of researchers claims.
The test, if validated in further studies, has the potential to serve as a cancer screening tool for individuals at elevated risk for bladder cancer due to genetics, smoking, or from environmental exposures to known carcinogens, and it could help to reduce the frequency of unnecessary cystoscopies, say urologists who were not involved in the research.
The test involved was performed using a next-generation sequencing assay (UroAmp, Convergent Genomics, based in San Francisco) that identifies mutations in 60 genes associated with bladder cancer. New research reported at the annual congress of the European Association of Urology described the screening model that focused on 10 key genes covered in the assay.
In training and validation cohorts, the urinary comprehensive genomic profiling test accurately predicted future bladder cancer in 66% of patient urine samples, including some that had been collected more than a decade prior to being tested, reported Florence Le Calvez-Kelm, PhD, MSc, from the International Agency for Research on Cancer, Lyon, France.
“Our results provide first evidence from a population-based cohort study of preclinical urothelial cancer detection with urinary comprehensive genomic profiling,” she told the meeting.
The results were consistent both in individuals with known risk factors for bladder cancer who were undergoing cystoscopy and in those with no evidence of disease, she said.
“Research of this nature is very encouraging, as it shows that our ability to identify molecular alterations in liquid biopsies such as urine that might indicate cancer is constantly improving,” commented Joost Boormans, MD, PhD, a urologist at the Erasmus University Medical Center, Rotterdam, Netherlands, and a member of the EAU Scientific Congress Office.
“While we do need to develop more accurate diagnostics, it’s unlikely that we’ll have a mass screening program for bladder cancer in the near future,” he continued. “Where a urine test for genetic mutations could show its value is in reducing cystoscopies and scans in bladder cancer patients who are being monitored for recurrence, as well as those referred for blood in their urine. A simple urine test would be far easier for patients to undergo than invasive procedures or scans, as well as being less costly for health services.”
Dr. Le Calvez-Kelm and colleagues had previously shown that promoter mutations in the gene encoding for the enzyme telomerase reverse transcriptase (TERT) identified in urine were “promising noninvasive biomarkers” for early detection of bladder cancer.
They found that TERT mutations in urine could predict which patients were likely to develop urothelial cancer with 48% sensitivity and 100% specificity.
In the study presented at EAU23, they hypothesized that uCGP of DNA in urine could offer enhanced sensitivity for early detection of urothelial cancer.
They first used the 60-gene assay to create a training set using urine samples from 46 patients with de novo urothelial cancer, 40 with recurrent cancer, and 140 healthy controls.
They then tested the model in two validation cohorts. The first validation cohort consisted of samples from 22 patients with de novo cancer, 48 with recurrent urothelial cancer, and 96 controls from a case-control study conducted at Massachusetts General Hospital, Boston, and Ohio State University, Columbus.
The second validation cohort included 29 patients from the prospective Golestan Cohort Study who subsequently developed urothelial cancer, with 98 controls.
In all, 10 genes were identified as optimal for inclusion in a screening model, which was trained to an overall sensitivity of 88% and a 97% sensitivity for high-grade tumors, with a specificity of 94%.
In the MGH/OSU validation cohort the sensitivity of the models was 71%, and the specificity was 94%. In the Golestan cohort, the sensitivity was 66%, with a specificity of 94%. This compared favorably with the performance of the TERT-only screening model, which, as noted before, had a sensitivity of 48%, albeit with 100% specificity.
“Interestingly, when we broke down the analysis according to the lag time between urine collection and diagnosis, sensitivity increased as the time to diagnosis decreased, so the closer we got to the diagnosis, the higher was the sensitivity,” Dr. Le Calvez-Kelm said.
When the analysis was limited to urothelial cancers diagnosed within 7 years of sample collection, the sensitivity for detecting preclinical cancer improved to 86%, compared with 57% for a test of TERT promoter mutations alone.
Among the patients in the Golestan cohort, uCGP-predicted positive results were associated with a more than eightfold higher risk for worse cancer-free survival, compared with uCGP-predicted negatives (hazard ratio 8.5, P < .0001).
“Of course, further studies are needed to validate this finding and to assess the clinical utility in other longitudinal cohorts,” Dr. Le Calvez-Kelm concluded.
A version of this article first appeared on Medscape.com.
