Dogs Sniffing Out Cancer

January 16th, 2014 by Leah Ingram

How researchers are teaching dogs to use their nose to detect hard-to-diagnose ovarian cancer.

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In the novel "The Art of Racing in the Rain" by Garth Stein, the story is told from a dog's point of view. That dog, Enzo, eventually smells cancer in his master and the reader suffers alongside him because he cannot "tell" his master what he smells.

As it turns out, the ability for dogs to smell cancer isn't fiction. Thanks to a unique joint program with the University of Pennsylvania's Working Dog Center, the Perelman School of Medicine at the University of Pennsylvania and the Monnell Chemical Senses Center (all in Philadelphia), researchers are "teaching" dogs to smell ovarian cancer so doctors can diagnose it sooner and save lives. That's because ovarian cancer, which kills 14,000 women each year, cannot be diagnosed through traditional testing. Often with ovarian cancer, once symptoms show up, it is too late to treat. In fact, that is the case with nearly 80 percent of women who die from ovarian cancer.

Cindy Otto, DVM, PhD, is executive director of Penn's Working Dog Center, which is part of the Veterinary Medicine School at Penn. In July 2013, thanks to an $80,000 grant from the Hope Ovarian Cancer Foundation, Otto began working with dogs to sniff out cancer. It's not really as farfetched as one might think: If dogs could be trained to sniff out bombs, bedbugs and even low blood sugar in diabetics, why can't they be trained to recognize the smell of ovarian cancer? Some dogs are already using their noses to detect cancer.

A dog in California gave its owner a heads up that she had breast cancer. The dog literally buried her head under her owner's right breast so many times that the owner felt around to see what she was going after and found a lump. A biopsy of that lump soon thereafter showed cancer. The British medical magazine The Lancet reported on a dog that kept going after a mole on his owner's leg – the mole turned out to be melanoma – as well as a Florida dermatologist who used K-9 training tactics to teach a dog to detect melanoma in patients.

Currently, Dr. Otto is working with three dogs. Two of the three seem to have already mastered the task of identifying the scent of ovarian cancer. They are McBaine, a springer spaniel, and Tsunami, a German Shepherd. She believes that the best breeds for these kinds of detection dogs are those with "a history of success in using their noses," she says, "and that's mostly related to whether they're hunting or working dogs." Labradors, German Shepherds and Spaniels all fit this description.

McBaine and Tsunami think their training is a game. To keep the dogs from getting bored, Dr. Otto changes up the training from day to day. One day she might use what's called a daisy wheel – a horizontal version of a game-show spinner, if you will, with metal cans on the end. Inside one of the cans Dr. Otto will place a chocolate chip-sized sample of tissue taken from someone with ovarian cancer. When the dog recognizes the scent, he sits. When he's right, he gets a treat. Another training method is to line up tubes of cut-up PVC pipe along a wall. "They walk along and sniff," she explains. "The majority of the PVC tubes have blanks in them." Again, if they smell cancer, they sit, and get a treat.

Each dog only spends about 10 minutes a day on each cancer sniffing training exercise. "We are going really slowly because we want to be sure the results are accurate," Dr. Otto explains. "We are training on tissue samples, and they are tiny. The amount of odor in tissue is relatively small. We are really asking dogs to perform something incredible. If we had a pound of this stuff, I bet they would have learned much faster."

Eventually, Dr. Otto will introduce other "distractors" into the training game, including other tissue samples and then the blood from those with ovarian cancer. While it would be wonderful to continue to have dogs in the lab, scientists in the field of oncology hope to one day replace the dogs with a machine that can "smell" cancer cells the way the dogs do. "Our goal is to use dogs to refine the chemistry, and turn it over to the more automated system," Dr. Otto explains. " The question we're hoping to answer is, can we develop a machine? If you've ever written computer programs, you know it is really hard to make it think like a man or an animal can. A dog can recognize an odor and tell us where it is, whereas with a machine you have to consider every contingency." For example, if you put perfume on an odor, "for the dog, yeah, it's still there," she adds, "but that perfume might overlap and mask the signature odor for a machine."

Dr. Otto's mission fits well with her background. She was the on-site veterinarian for the search and rescue dogs after September 11th. "I was deployed to Ground Zero to take care of the dogs," she recalls. She has been working with what she calls detection dogs for 20 years, and started the Penn Working Dog Center in 2012 to meld science with dogs’ innate ability to work in ways that help humans – be it rescuing them from dangerous situations, aiding their police partners in pursuit of criminals, or detecting cancer in ways people could have never imagined.

Leah Ingram is the author of 14 non-fiction books, including "Suddenly Frugal: How to Live Happier and Healthier for Less." That book grew out of her popular frugal-living blog called Suddenly Frugal.