It is estimated that 233,000 men in the US will be diagnosed with prostate cancer this year. Although current screening methods for the disease - such as digital rectal exams - aid early detection, they are not always accurate. But with the help of "man's best friend," a new screening technique could be in the cards.
A new study from Italian researchers, presented at the 109th Annual Scientific Meeting of the American Urological Association in Orlando, FL, found that specially trained dogs were able to detect prostate cancer from urine samples with 98% accuracy.
There is no denying a dog's extraordinary sense of smell. While we have around 5 million olfactory cells in our noses - receptors that detect different odors - dogs have approximately 200 million. It is dogs' acute ability to trace scents that has made them so attractive to the medical world.
In November last year, a spotlight feature from Medical News Today delved into the world of medical detection dogs. The feature looked at how the animals can help alert a diabetic owner to high or low blood sugar levels through being trained to detect a specific scent in their breath or sweat.
The feature also explored how dogs are now being used for detection of various cancers. One study revealed that trained detection dogs were able to detect ovarian cancer in tissue and blood samples through sniffing out volatile organic compounds (VOCs). A 2011 study, conducted by researchers at UK charity Medical Detection Dogs, found that such compounds could also be biomarkers of bladder cancer.
The authors of this latest research note that in 2010, a study demonstrated that specially trained dogs were able to smell VOCs released into urine from prostate cancer tumors. But this study only involved 33 patients. Therefore, the Italian research team set out to determine dogs' detection accuracy in a larger sample.
A 'promising approach' to cancer detection
For their study, the team wanted to see whether two highly trained dogs were able to detect prostate cancer-specific VOCs in the urine samples of 677 participants. Of these, 320 had prostate cancer ranging from low-risk to metastatic and 357 were healthy controls.
Researchers found that two highly trained dogs were able to detect prostate cancer in urine samples with a combined 98% accuracy.
All testing was carried out in an environment that was free of olfactory disturbance, according to the team.
They found that the dogs were able to detect prostate cancer-specific VOCs in the urine samples with a combined accuracy of 98%. Sensitivity to the compounds was 99% accurate, while specificity was 97% accurate.
The first dog's overall accuracy for detecting VOCs was 99%, while sensitivity was 100% and specificity was 98%. The second dog was able to detect VOCs with 97% accuracy, while sensitivity was 99% accurate and specificity was 96% accurate.
Dr. Brian Stork, a urologist as West Shore Urology in Muskegon and Grand Haven, MI, who was not involved in the study but conducted the presentation, comments:
"These data show analysis of volatile organic compounds in urine is a promising approach to cancer detection.
The possibility of using dogs to identify 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."
It is not only dogs' intricate sense of smell that has caught the interest of medical researchers. Earlier this year, Medical News Today reported on a study revealing that dogs could provide new insight into Chiari malformation in humans - a condition that occurs when the lower parts of the brain are pushed down toward the spinal cord.
Other research published in Genome Biology found that dogs could serve as a model for obsessive compulsive disorder (OCD) in humans.