Testing for genetic changes in urine can detect bladder cancer years before clinical symptoms appear, according to a recent study. Researchers from France, Iran and the United States have discovered abnormalities in 10 genes that could predict the most common type of bladder cancer up to 12 years before diagnosis.
Bladder cancer is not a rare disease
The findings are being presented today at the European Urological Association (EAU) Annual Congress in Milan. Bladder cancer is not a rare disease – it is one of the ten most common cancers in the UK and the fifth most common in the European Union, with more than 200,000 cases in the EU each year.
Only about half of those diagnosed with advanced disease survive more than five years, mainly because of late diagnosis and disease recurrence. In contrast, if their cancer is detected at an early stage, more than 80% of patients survive at least five years.
Lead researcher Dr Florence Le Calvez-Kelm, from the International Agency for Research on Cancer (IARC) in Lyon, said: “The diagnosis of bladder cancer relies on expensive and invasive procedures such as cystoscopy, which involves inserting a camera into the bladder.
A simpler urine test that could accurately diagnose and even predict the likelihood of cancer years in advance could help detect more cancers at an early stage and avoid unnecessary cystoscopies in healthy patients.”
The study was based on the UroAmp test, a general urine test that identifies mutations in 60 genes, developed by Oregon Health Science University’s Convergent Genomics. Building on previous research to identify genetic mutations associated with bladder cancer, the research team narrowed the new test down to target mutations within just ten genes.
Working with colleagues at Tehran University of Medical Sciences in Iran, they tested the potential new test using samples from the Golestan Cohort Study, which followed the health of more than 50,000 participants over a decade, all of whom provided urine samples at recruitment. Forty people in the study developed bladder cancer during that decade, and the team was able to test urine samples from twenty-nine of them, along with samples from 98 other similar participants as controls.
Of the 29 participants who developed bladder cancer in the Golestan cohort, the test was able to accurately predict future bladder cancer in 19 (66%) of them, even though urine samples were collected up to 12 years before clinical diagnosis. Fourteen of these participants were diagnosed with bladder cancer within seven years of urine collection, and the test was able to predict cancer in 12 (86%) of them.
The test was exactly negative in 94 of 98 participants (96%), who will not develop cancer in the future. Among those who tested negative but eventually developed bladder cancer, no cancer was diagnosed until at least six years after the urine collection.
The test was also tested with colleagues from Massachusetts General Hospital and Ohio State University, using samples from 70 bladder cancer patients and 96 controls, taken before cystoscopy. Unlike the Golestan study, some of these samples were provided by cancer patients on the day they were diagnosed, rather than many years ago.
Mutations were found in urine samples from 50 of 70 patients (71%) whose tumors were visible during cystoscopy. Some of these were new diagnoses and others involved recurrent cancer. Mutations were not found in 90 of 96 (94%) patients with negative cystoscopy.
Dr. Le Calvez-Kelm believes these results demonstrate the potential of a genetic urine test for the early detection of bladder cancer. She said: “We have clearly identified which are the most important acquired genetic mutations that can significantly increase the risk of developing cancer within ten years. Our results were consistent across two very different groups—those with known risk factors undergoing cystoscopy and individuals assumed to be healthy.
“If the results were replicated in larger cohorts, urine tests for these mutations could allow routine screening of high-risk groups, such as smokers or those exposed to known bladder carcinogens in their work.” This kind of test can also be used when patients come to their doctor with blood in their urine to help reduce unnecessary cystoscopies. If we can identify bladder cancer early, before the disease progresses, we can save more lives,” she added.
Dr Joost Boormans, member of the EAU Scientific Congress Office and urologist at the Erasmus University Medical Center in Rotterdam, said: “Research of this nature is very encouraging as it shows that our ability to identify molecular changes in liquid biopsies such as urine can indicate that the cancer keeps getting better.
“Although we need to develop more accurate diagnostics, it is unlikely that we will have a mass screening program for bladder cancer in the near future.” A urine test for genetic mutations could show value in reducing cystoscopies and scans for bladder cancer patients being monitored for recurrence, as well as patients being referred for blood in the urine. A simple urine test would be much easier for patients to undergo than invasive procedures or scans and would also be less expensive for health services,” added Boormans.
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