Can Dogs Smell Sickness?

I recently read an article entitled: Training Dogs to Sniff Out Cancer in the NY Times.

This article states that in Philidelphia a springer spaniel works at the Veteran Center and is being trained to find differences in different types of blood plasma.  His nose skims 12 tiny arms that protrude from the edges of a table-size wheel, each holding samples of blood plasma, where only one of which is spiked with a drop of cancerous tissue. He does so and he gets a treat!

This dog is named McBaine.  He is one of four highly trained cancer detection dogs at the center, which trains purebreds to put their superior sense of smell to work in search of the early signs of cancer.

Since 2004, research has been suggesting that dogs may be able to smell the subtle chemical differences between healthy and cancerous tissue.

Dogs have already been trained to respond to diabetic emergencies or alert passers-by if an owner is about to have a seizure.

A study presented at the American Urological Association’s annual meeting in May reported that two German shepherds trained at the Italian Ministry of Defense’s Military Veterinary Center in Grosseto were able to detect prostate cancer in urine with about 98 percent accuracy, far better than the prostate-specific antigen (PSA) test that is normally given to patients.   That is really amazing.  Dogs are so wonderful!

The dogs, are raised in the homes of volunteer foster families, and start with basic obedience classes when they are eight weeks old. They then begin their training in earnest, with the goal of teaching them that sniffing everything — from ticking bombs to malignant tumors — is rewarding.

What exactly are the dogs sensing? George Preti, a chemist at the Monell Chemical Senses Center in Philadelphia, has spent much of his career trying to isolate the volatile chemicals behind cancer’s unique odor. “We have known for a long time that dogs are very sensitive detectors,” Dr. Preti says.

Dr. Preti is working to isolate unique chemical biomarkers responsible for ovarian cancer’s subtle smell using high-tech spectrometers and chromatographs. Once he identifies a promising compound, he tests whether the dogs respond to that chemical in the same way that they respond to actual ovarian cancer tissue.

“I’m not embarrassed to say that a dog is better than my instruments,” Dr. Preti says.

Some experts remain skeptical and I am sure there is more research to be done before it is utilized in a medical setting, but it could be very interesting if dogs have the capability of detecting such things.  Wouldn’t it be better than getting an invasive procedure?