It sounds incredible, but research has proved it once and again: dogs are able to detect cancer, even in early stages, just by sniffing urine samples. Scientists explain that malignant tumour related volatile organic compounds are present in urine, imparting a characteristic odour signature, quickly identified by these animals. The first serious trial was conducted in England in 2004, focusing on bladder cancer. Now there is evidence indicating that dogs can assist to diagnose lung, bowel, prostate and breast cancer.
And, to encourage progress in this field, a specific charity was formed in the United Kingdom in 2007, Cancer and Bio-detection Dogs. The process of training and qualifying the dogs is long and expensive. It's based in positive reinforcement; the dogs are offered rewards when they locate the correct scent. It all takes around two years, and costs nearly 10.000 pounds/12.000 euros. Puppies and also adult dogs are usually donated. They come from breeders or welfare groups. As they are selected according to their olfactory capacities, the charity trains dogs of a wide variety of breeds. They usually start their training when they are from eight to sixteen months old, depending on their particular features.
The bio-detection dogs live with their families, leading normal pet lives. They play ball, take walks... and, also, go to work two or three days a week. Their working hours are kept short, and the sessions are interspersed with play periods and resting. The point is the dogs enjoy their job and don't get tired. They are shown the samples they must sniff by means of a device called “carousel”.
Up to the moment they are not trained to smell people, but recent studies indicate that cancer volatiles may appear also on the patients' breath, so nothing can be ruled out.