ORLANDO – Specially trained dogs accurately detected specific prostate cancer volatile organic compounds in urine samples from patients with varying stages of disease and risk levels in a controlled study.
One dog was able to distinguish 320 urine samples taken from prostate cancer patients from 357 control samples with 100% sensitivity, 97.8% specificity, and 98.9% accuracy. A second dog performed with 98.6% sensitivity, 95.9% specificity, and 97.3% accuracy, Dr. Gianluigi Taverna of Humanitas Research Hospital, Milan, reported at the annual meeting of the American Urological Association.
The combined performance of the dogs – German shepherds trained by a dedicated research team using hundreds of urine samples over several months – resulted in 98.1% accuracy, 99.2% sensitivity, and 97.1% specificity.
Samples used in the study were from prostate cancer patients with cancer raging from very low risk disease to metastatic disease, and controls were a heterogeneous cohort of healthy subjects or patients affected by nonneoplastic diseases or nonprostatic tumors.
An evaluation of the wrongly detected cases showed that there were no differences in the specimens with respect to epidemiological, clinical, or histopathological characteristics, Dr. Taverna said.
Interest in the analysis of volatile organic compounds (VOCs) in urine is increasing, as this is considered a promising approach to cancer detection, and based on the findings of the current study it appears that a rigorously trained canine olfactory system can recognize prostate cancer VOCs, and thus represents a "real clinical opportunity" to reduce unnecessary biopsies and identify patients at high risk for prostate cancer, he concluded.
Dr. Brian Stork of West Shore Urology, Muskegon, Michigan, who moderated a press briefing where the findings were presented, said that the data highlight the potential value of VOCs in urine as a means for cancer detection.
"The possibility of using dogs in identifying cancer is something most would never have considered possible a decade or two ago. It’s an interesting concept that ‘man’s best friend’ could help save your life," he said in press statement.
It has been long known, however, that dogs have a highly sensitive olfactory system, with roughly 200 million olfactory cells in their noses, compared with about 5 million for humans, and interest in tapping their potential in medicine has been on the rise. Research has shown that dogs are capable of detecting epileptic seizure onset, and breast and lung malignancies through the detection of VOCs. In 2010, a small study of 33 patients suggested that dogs could detect prostate cancer VOCs in urine; the current study, in a much larger cohort, confirms those findings.
Dr. Taverna reported having no disclosures.