Dogs trained to sniff out bladder cancer in human urine

• In a novel experiment, a team of scientists and dog trainers have put this traditional canine behaviour to good use -- sniffing human urine to detect bladder cancer sufferers.
• The researchers hope that analysis and identification of the characteristic chemical odorants may lead to non-invasive, early-detection screening methods for bladder cancer in the future.
• "There had been a series of anecdotal stories about patients whose pet dogs had aroused concern by continually sniffing their moles, which actually turned out to be cancerous.
• I was pretty sceptical and needed to design a simple experiment to test it," explained the study's lead author, Carolyn Willis, from Amersham Hospital in the UK.
• The impracticalities of training dogs to detect skin cancer using skin biopsies led Willis and colleagues to consider trying bladder cancer detection, using easily obtainable urine samples.
• Six dogs of varying ages and breeds underwent a seven month training course in cancer detection, carried out by trainers from Hearing Dogs for the Deaf.
• "We wanted to make sure it was the cancer they were smelling, so we ruled out other urine abnormalities by having control samples with blood, proteins, leukocytes and other abnormalities by using urine from patients with non-cancerous urological disorders," Willis said.
• In the final, double-blind experiment, each dog underwent nine separate tests in which they were shown an array of seven urine samples, one of which was cancerous, and told to lie down next to the cancerous one.
• These volatile organic chemicals may include alkanes and alkenes, they believe.
• It is detected using cystoscopy -- inserting a fibre-optic instrument into the bladder via the urethra.
• Since it commonly recurs, patients who survive the cancer must undergo regular cystoscopy as a form of screening.