dogs smell cancer Midas
Can dogs smell cancer?
02:21 - Source: CNN

Editor’s Note: Vital Signs is a monthly program bringing viewers health stories from around the world

Story highlights

Dogs' noses have 300 million sensors, compared with a human's 5 million

Some dogs can detect cancer's unique odors called volatile organic compounds

Milton Keynes, United Kingdom CNN  — 

Lucy, a cross between a Labrador retriever and an Irish water spaniel, failed miserably at guide dog school. As she was curious and easily excitable, random scents distracted Lucy from her master’s path, and it wasn’t long before she was unceremoniously kicked out.

But her owners knew their smart dog held promise. They decided, if her nose was getting her into trouble (she was after all, bred to be a hunting dog), why not train her to sniff out something useful?

For the next seven years,