Carolyn Withers is convinced that her dog Myles saved her life.
In September 1999 she says her normally laid-back Labrador retriever started jumping, barking and poking his nose under her arm, near her right breast. At first she thought nothing of it. Then one night, she could no longer ignore him.
"I had gone to bed and Myles actually lunged right onto the bed, and he never did that," Withers said. "And he, you know, dodged right towards my arm area, and started barking. He was in a panic. And that's when all of a sudden I felt this real fear."
After doing a breast self-examination, she found what felt like a small pearl. She says she knew immediately that it was cancer. Withers had surgery and is now fine.
Was it coincidence? Did Myles really detect the cancer? Is this possible? Manhattan veterinarian Andrew Kaplan said we'd be amazed at the information a dog's nose might provide because "a dog has approximately 220 million smell receptors in their nose, and people have about 5 million."
The idea that dogs can smell cancer has intrigued doctors and scientists and led to a number of studies. Amersham Hospital, outside of London, trained dogs to smell bladder cancer in urine. The head of the research team, Carolyn Willis, says they used urine because "the smelly chemicals that are released from the bladder cancer go directly into the urine so it's a very good model for us to use."
In these kinds of studies, the dogs are trained for the task at hand. Willis explains that the trainers started with just two urine samples — "One would be from a bladder cancer patient, the other one from a normal healthy volunteer. And the dog had to choose the bladder cancer one and, if it did, then it was rewarded."
Willis was initially skeptical about the idea, but by the end of the study was convinced that dogs can indeed smell certain cancers.
The Amersham study was published in the British Medical Journal three years ago. "Certainly our experiment was very carefully controlled, stood up to a lot of rigorous viewing by statisticians and by the medical profession and I am certain that dogs can pick up the odor of bladder cancer," Willis said.
The hospital has started a second study of bladder and prostate cancers in urine. A spaniel named Tangle has an excellent track record in this second study. He is up to 70 percent or 80 percent accuracy. The study is ongoing.
California's Pine Street Foundation studied canine scent detection in early and late-stage lung and breast cancer. In this case, breath samples were collected in tubes with polypropylene fibers. Michael McCulloch of Pine Street says the study placed a tube from a cancer patient on the floor amid four others from healthy individuals.
says the dogs "nailed it 90 percent of the time in thousands of trials." This study appeared last year in the journal Integrative Cancer Therapies.
It certainly appears that dogs can be trained to smell cancer — just as they can be trained to sniff bombs or drugs. But what exactly are they smelling? The dogs can't tell us … so science is working on it.