can prostate cancer smelling dogs be far behind?
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Thursday, September 23, 2004

A dog's sense of smell is up to 100,000 times better than a human's.

LONDON, England (AP) -- We have always suspected that man's best friend
has a special ability to sense when something is wrong with us, but the
first experiment to verify that scientifically has demonstrated that
dogs are able to smell cancer.

Experts say it is unlikely that pooches will become practical partners
in cancer detection any time soon, but that the results of the study by
English scientists are promising.

They showed that when urine from bladder cancer patients was set out
among samples from healthy people or those with other diseases, the dogs
-- ordinary pets -- were able to identify the cancer urine almost three
times more often than would be expected by chance alone.

"The issue is not whether or not they can detect cancer, because clearly
they can. The issue is whether you can set up a system whereby they can
communicate with you. That requires further ingenuity," said Tim Cole, a
professor of medical statistics at Imperial College in London, who was
not connected with the research but is the owner of a labrador
retriever.
David Neal, a bladder and prostate cancer surgeon at Cambridge
University in England, said it was plausible that dogs might be able to
pick up the scent of cancer because people with the disease shed unique
abnormal proteins in their urine.

"I'm skeptical about whether it will be implementable, but
scientifically it should be followed up," said Neal, a spokesman for
Cancer Research UK, Britain's cancer society, who was not involved in
the research.
"It might be that the dogs are better than our current machines at
picking up abnormal proteins in the urine. What are the dogs picking up?
Can we get a machine that does the same?"

It is thought that a dog's sense of smell is generally 10,000 to 100,000
times better than a human's.

The idea that they may be able to smell cancer was first put forward in
1989 by two London dermatologists, who described the case of a woman
asking for a mole to be cut out of her leg because her dog would
constantly sniff at it, even through her trousers, but ignore all her
other moles.

One day, the dog had tried to bite the mole off when the woman was
wearing shorts.

It turned out she had malignant melanoma -- a deadly form of skin
cancer. But it was caught early enough to save her life.

Then in 2001, another pair of English doctors reported a similar case of
a man with a patch of eczema on his leg for 18 years, until one day his
pet labrador started to persistently sniff the patch, again through his
trousers.
It turned out the man had developed skin cancer and, once the tumor was
cut out, the dog showed no further interest in the eczema patch.

Anecdotal evidence

A handful of similar anecdotes have since been reported, but the latest
study is the first rigorous test of the theory to be published.

The experiment, conducted by researchers at Amersham Hospital in England
and the nearby organization Hearing Dogs for Deaf People and published
in this week's British Medical Journal, set out to prove whether dogs
could be trained to pick out cancer.
Six dogs -- all the pets of the trainers -- were used in the study. They
included three working-strain cocker spaniels, one papillon, a labrador
and a mongrel.
The trainers used urine from bladder cancer patients, from people sick
with unrelated diseases and some from healthy people to train the dogs
over seven months to zone in on the cancer-unique elements by process of
elimination.
They learned to ignore differences in the urine samples that were due to
age, sex, infection, diet and other factors.
Urine from 36 bladder cancer patients and 108 comparison volunteers was
used. Some samples were kept back for the test, whereby each dog had to
sniff seven urine samples in one room and lie down next to the one from
a bladder cancer patient.

The test was repeated eight times for each dog with new urine samples
every time.

Signal varies

Taken as a group, they correctly selected the right urine on 22 out of
54 occasions, giving an average success rate of 41 percent. By chance
alone, you'd expect them to be accurate one-seventh, or 14 percent, of
the time.

The two best dogs, Tangle and Biddy -- both cocker spaniels -- were
right 56 percent of the time, according to trainer Andrew Cook. They all
did well, except for one: Toddy the mongrel.

"Toddy, bless him, was working at a rate no better than chance, really,
but we still love him," Cook said.

One of the cancer patients was identified correctly by all six dogs,
whereas two other cancer patients were consistently missed, indicating
that perhaps the strength of the urine signal varies from person to
person, or according to severity of the disease.

Perhaps the most intriguing finding, though, was in a comparison patient
whose urine was used during the training phase.

All the dogs unequivocally identified that urine as a cancer case, even
though screening tests before the experiment had shown no cancer.

Doctors conducted more detailed tests on the patient and found a
life-threatening tumor in the right kidney.

Copyright 2004 The Associated Press.

 

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."