They're man's best friend, but dogs, it turns out, may also be a doctor's newest secret weapon for detecting cancer.
LOEFFINGEN, GERMANY (AUGUST 24, 2011) REUTERS - Dog trainer Uwe Friedrich in Loeffingen can rely on Bonni's nose. The German shepherd can sniff out with great reliability whether a person has lung cancer - from a sample of the person's breath.
Like Bonni Friedrich has trained several other dogs in his training school in the Black Forest. As with other sniffer dogs the principle of 'cancer sniffing' works on the reward basis. The dogs are trained to lie down when they detect a cancer sample and can look forward to receiving a treat.
"We trained the dogs via positive stimulation. So the smell of cancer is regarded as lucrative, positive by our dogs," Friedrich said. "We trained them to lie down when they sniff a cancer sample. And that worked through positive stimulation. We had a large amount of samples, more than 200, and the dogs had to differ between cancer and not cancer."
What looks like a fun exercise is more than just fun. Friedrich works together with doctors at the clinic 'Schillerhoehe' in Gerlingen. Especially lung diseases are researched and treated here. Because lung cancer seems to have a specific combination of odours, the scientist thought of using the very fine nose of dogs to detect it.
The German shepherd's dog Bonni, the labrador retriever Hector and the Australian shepherd's dog Benny started with her training roughly two years ago to detect the difference between various lung cancer and healthy samples. After a while the sniffer noses delivered what was hoped for. The chest surgeon Enole Boedeker speaks of a hit rate of 72 percent.
And the dogs have a huge advantage compared to 'normal' electronic noses.
"The electronic noses are extremely sensitive to influences like diet, like what the people drank, if they drank alcohol, or if they smokes cigarettes," Boedeker told Reuters TV. "And the dogs just don't bother. They can easily find the lung cancer beside all other influences." The dogs can also detect a difference between patients who have been
suffering for some time from lung cancer compared to those who have just recently fallen ill.
While there has been some precedent for disease-sniffing dogs - in other studies, they have had anywhere from 40 to 90 percent success in accurately identifying cancers including bladder and colon cancers, not to mention their ability to sniff out low blood sugar levels among diabetics - more work needs to be done before dogs become part of a clinical workup.