The idea that dogs might be able to smell or detect cancer in people has been around for a while, but several studies have recently begun to provide stronger evidence to back up these reports.
In addition to already being evidence that dogs feel people’s pain and seek to alleviate it, today, the United Kingdom’s National Health Service (NHS) has also approved the use of dogs for cancer detection in trials to test its ability to detect prostate cancer. Initial studies have found that dogs can successfully detect prostate cancer in 93% of cases.
“Over the years, there have been many anecdotal reports suggesting that dogs may be able to detect cancer based on the smell of the tumor,” explained Iqbal Anjum, a consultant urologist at Milton Keynes University Hospital, where the trials took place. “The volatile molecules associated with the tumor are supposed to be released into the person’s urine, making samples easy to collect and test.”
The current test for prostate cancer in men over 50 is called the prostate specific antigen (PSA) test. This is a blood test that examines the levels of a particular molecule secreted by the prostate that is often – though not always – elevated in those who have prostate cancer.
While it is estimated that one in eight men will develop the disease, it is believed that the PSA blood test does not detect cancer in 20% of those who have it, and gives many false positive results. This means that many men who do not have the disease are often referred for invasive biopsies.
It is hoped that, with the use of dogs as a second tier in a screening process that involves PSA testing first, clinicians will be able to more accurately arrive at tests for cancer, reducing the number of unnecessary biopsies. Dogs are trained to identify cancer by inhaling a urine sample taken from the patient.
Dogs’ extraordinary sense of smell – capable of detecting parts per trillion – is thought to allow them to detect certain “volatile” particles that travel from prostate cancer in urine.
“Britain has one of the worst early cancer detection rates in Europe,” explained Dr. Claire Guests, who founded the Medical Detection Dogs charity , which runs the trials. “The NHS needs to be bolder about introducing new innovative methods to detect cancer in its early stages.
Our dogs have higher reliability rates than most existing tests. We shouldn’t be turning our backs on these highly sensitive bio-detectors just because they have furry coats. “