9 March 2014 Last updated at 02:47
Sniffing out cancer with electronic noses
By William Kremer BBC World Service
We may soon be able to obtain easy and early diagnoses of diseases by smell. This week researchers found one odour-sniffing machine was as good as a mammogram at detecting breast cancer - and many other devices capable of spotting other diseases may be on the way.
"I may sound crazy but I'm not," writes Joanie, on an online support forum for people affected by cancer. She relates how, while her husband suffered from prostate cancer, she could smell "an odour similar to decay". It went away with the cancer, but in 2012 she was alarmed to smell the putrid stench once again. Not long afterwards, Joanie herself was diagnosed with lung cancer.
Although many cancer sufferers and their relatives do not notice a nasty smell, Joanie's experience is not unusual. "I've had numerous people writing to me about this," says George Preti from the Monell Chemical Senses Center in Philadelphia. "I've had lots of notes from nurses and researchers in the area, but they're mostly anecdotal reports."
Throughout history, doctors have sniffed their patients' breath, urine, stool and other bodily fluids to help with diagnoses. A 2011 review article featured "smelling notes" of dozens of diseases. Yellow fever is said to smell like a butcher's shop, liver failure like raw fish, and typhoid like freshly baked brown bread.
A recent experiment also provides some evidence that people give off a bad smell as they fall sick.
http://www.bbc.co.uk/news/magazine-26472225