Study: Dogs Could Provide Greater Service for Prostate Cancer Screenings

March 22, 2021
Jill Murphy, Associate Editor

Clinicians have been searching for accurate, reliable, non-invasive diagnostic tools to differentiate early stage, less dangerous, and more treatable stages of the disease from the aggressive, high-grade and likely-to-spread forms.

Researchers at The Johns Hopkins Hospital have found that a dog’s sensitive sense of smell can help improve testing for prostate cancer, according to a press release.

Clinicians have been searching for accurate, reliable, non-invasive diagnostic tools to differentiate early stage, less dangerous, and more treatable stages of the disease from the aggressive, high-grade and likely-to-spread forms. Standard blood tests for early detection often miss cancers in men whose prostate-specific antigen levels are within normal levels or over-diagnose men with clinically insignificant tumors or no cancer at all, according to the study authors.

The research team had 2 dogs sniff samples of urine from men diagnosed with high-grade prostate cancer and from men without cancer. The animals, Florin, a 4-year-old female Labrador, and Midas, a 7-year-old female wire-haired Hungarian vizsla, had been trained to respond to cancer-related chemicals, also known as volatile organic compounds (VOCs), added to urine samples and not respond to ones without them.

"Besides PSA, other methods to detect prostate cancer make use of a molecular analyzer called a gas chromatography-mass spectrometer [GC-MS] to find specific VOCs or profiling bacterial population in a urine sample looking for species associated with cancer, but these have limitations," said urologist-in-chief at The Johns Hopkins Hospital, Alan Partin, MD, PhD, in a press release. "We wondered if having the dogs detect the chemicals, combined with analysis by GC-MS, bacterial profiling and an artificial intelligence [AI] neural network trained to emulate the canine cancer detection ability, could significantly improve the diagnosis of high-grade prostate cancer."

Further, adding AI analysis helped the researchers filter the more than 1000 VOCs present in a typical urine sample down to those most beneficial for cancer diagnosis. The dogs performed their cancer detection roles well, identifying 5 of 7 urine samples from men with cancer, with 71.4% accuracy. Florin was able to correctly identify 16 of the 21 non-aggressive or no cancer samples (76.2%), whereas Midas was able to pick out 14 (66.7%), according to the study authors.

When the canine smell results were combined with GC-MS, bacterial profiling, and AI analysis, the multisystem approach proved a more sensitive and more specific means of detecting lethal prostate cancer than any of the methods alone.

The study authors noted that this study was made possible because of a long history of “biobanking” valuable patient samples.

"Larger sample pools will be the key enabler of statistically powered, multi-institutional future studies seeking to fully integrate VOC and microbiota profiling," Partin said in a press release.

REFERENCE

Man’s best friend could help save him from prostate cancer. EurekAlert! Published March 17, 2021. Accessed March 19, 2021. https://new.eurekalert.org/pub_releases/2021-03/jhm-stf031721.php