Professor Chris Probert
Courtesy: University of Liverpool
A pilot study conducted by researchers from the University of Liverpool shows promising results for a new diagnostic tool that can “smell” prostate and bladder cancer in urine.
This new system could potentially transform prostate cancer diagnosis, which commonly consists of the controversial prostate-specific antigen (PSA) test.
Prostate cancer is the second most common cancer among U.S. men, according to the CDC — and yet, accurately diagnosing it continues to be a challenge. Research published in a 2005 issue of JAMA found that there was no PSA cutoff value with both high sensitivity and specificity to prostate cancer.
The standard cutoff value (4.1 ng/mL) yielded sensitivity of 20.5 percent and specificity of 93.8 percent, whereas the lowest cutoff value (1.1 ng/mL) produced sensitivity of 83.4 percent and specificity of 38.9 percent. Depending on the cutoff value used, men screened with the PSA test face either rampant overdiagnosis – and the invasive procedures, overtreatment, and anxiety that accompany it – or a missed cancer diagnosis.
Following the discovery that dogs can smell out urologic cancers with high accuracy, a research team – led by Chris Probert, a gastroenterologist at the University of Liverpool’s Institute of Translational Medicine, and Norman Ratcliffe, a professor at UWE Bristol – developed the Odoreader, a gas chromatography (GC)-sensor system that Ratcliffe likened to an electronic nose.
HCB News reached out to Probert via e-mail to get a better understanding of his team’s findings.
When a urine sample is inserted into the Odoreader, it separates the volatile organic compounds (VOCs) in urine into readable patterns, which are then analyzed by computer algorithms also developed by the research team.
The results of a pilot study, published Feb. 11 in the Journal of Breath Research, suggest that the GC-sensor algorithm system is able to successfully identify urologic cancers based on VOC patterns.
Their research consisted of 155 men presenting to urology clinics in Bristol. Of those patients, 58 were diagnosed with prostate cancer, 24 with bladder cancer, and 73 with symptoms such as hematuria, but not presenting cancer. Results varied depending on the statistical model used, but Probert summarized findings thusly: “For bladder cancer, the test was >96 percent sensitive/specific, for prostate cancer about 90 percent.”
These results hold promise that a non-invasive prostate cancer screening test yielding both high sensitivity and specificity may soon make its way into health care practices.
Going forward, the team hopes to fund a full clinical trial and work with industry partners to develop the Odoreader into a scalable format. And while the focus of the pilot study was on prostate cancer, Probert said that in upcoming bladder cancer work, they will be studying the Odoreader as a screening tool for women, as well. In the longer term, they also intend to trial the Odoreader as a diagnostic tool for other forms of urologic cancers, such as testicular and kidney cancer.
The research team is concurrently studying the efficacy of this diagnostic method on Probert’s primary research interest, inflammatory bowel disease. In a statement, he said the group is planning to publish those findings in the near future.