Over the past 10 years, a lot of research has been done to determine if dogs can can help in the early detection of cancer by using their keen sense of smell. The following article describes the early positive results of  using the power of a dog’s nose to sniff out cancers such as breast, bladder and prostate cancer: http://blogs.telegraph.co.uk/news/judithpotts/100189318/the-dogs-who-can-smell-cancer/

In France, the French military is running it’s own study on the possibility of using dogs for the early detection of prostate cancer.  These efforts are described in the following article (french): http://selection.readersdigest.ca/magazine/un-chien-contre-le-cancer.  The dog described in the article required over 15 months of intensive training before he could start identifying human urine with traces of prostate cancer.  His first official tests in 2009 were fairly conclusive: the dog, a Belgian shepherd dog, successfully identified 30 of 33 of the positive samples.

Hopefully, research like this will help in developing a non intrusive method for a detecting early signs of cancer.