2004-10-5
This is Gwen Outen with the VOA Special English Health Report.
Dogs are known for their sense of smell. They can find missing
people and things like bombs and illegal drugs. Now a study suggests
that the animal known as man's best friend can even find bladder
cancer.
Cancer cells are thought to produce chemicals with unusual odors.
Researchers think dogs have the ability to smell these odors, even
in very small amounts, in urine. The sense of smell in dogs is
thousands of times better than in humans.
The study follows reports of cases where, for example, a dog
showed great interest in a growth on the leg of its owner. The mole
was later found to be skin cancer.
Carolyn Willis led a team of researchers at Amersham Hospital in
England. They trained different kinds of dogs for the experiment.
The study involved urine collected from bladder cancer patients,
from people with other diseases and from healthy people.
Each dog was tested eight times. In each test there were seven
samples for the dogs to smell. The dog was supposed to signal the
one from a bladder cancer patient by lying down next to it.
Two cocker spaniels were correct fifty-six percent of the time.
But the scientists reported an average success rate of forty-one
percent.
As a group, the study found that the dogs chose the correct
sample twenty-two out of fifty-four times. That is almost three
times more often than would be expected by chance alone.
The British Medical Journal published the research. In all,
thirty-six bladder cancer patients and one hundred eight other
people took part.
During training, all the dogs reportedly even identified a cancer
in a person who had tested healthy before the study. Doctors found a
growth on the person's right kidney.
Carolyn Willis says dogs could help scientists identify the
compounds produced by bladder cancer. That information could then be
used to develop machines to test for the chemicals. Now, doctors
must remove tissue from the bladder to test for cancer. The team
also plans to use dogs to help identify markers for other kinds of
cancer.
Bladder cancer is the ninth most common cancer worldwide. The
International Agency for Research on Cancer says this disease kills
more than one hundred thousand people each year. Doctors say
cigarette smoking is the leading cause of bladder cancer.
This VOA Special English Health Report was written by Cynthia
Kirk. This is Gwen Outen.