Dogs' Ability to Detect Cancer by Smell Examined
GUPTA: The benefits of being around animals are pretty obvious, but that is not the only way our four-legged friends are helping our health. Elephants may provide crucial clues in the fight against cancer for humans. Even though they have 100 times as many cells as we do, elephants rarely get cancer. A study found the cancer mortality rates for these animals is less than five percent. That's compared to 25 percent in humans. Scientists believe the key is an excess of a certain protein that inhibits cancer cells. Meanwhile in the United Kingdom, dogs are helping us detect cancer. My colleague Elizabeth Cohen traveled to the U.K. to meet with these amazing dogs and their bio-sensing noses.</s>DR. ELIZABETH COHEN, CNN SENIOR MEDICAL CORRESPONDENT: Dr. Claire Guest is CEO of the charity Medical Detection Dogs based in England. For years she has claimed she can train dogs to smell cancer cells. And now her dogs are taking part in one of the largest clinical trials of canine cancer detection. Dr. Guest is a believer because she says her dog Daisy caught her own cancer six years ago. Claire, you said that a dog caught your cancer?</s>DR. CLAIRE GUEST, CEO, MEDICAL DETECTION DOGS: That's right. I was actually working on a cancer detection project and working with the dog during this time. She started to behave slightly differently around me, and she kept staring at me and looking into my chest. And it led me to find a lump. I had the lump checked by a DP, and I was referred to a specialist, and I had a diagnosis of a very grade breast cancer. I was told had my attention not drawn to it by Daisy that my prognosis would have been very poor.</s>COHEN: Dr. Guest started Medical Protection Dogs in 2008. The charity trains multiple teams, medical alert assistance dogs, for example, paired with diabetics to sniff out change in blood sugar levels and the cancer detection dogs. Why do we need dogs? There are plenty of tests to detect cancer.</s>GUEST: There are plenty of tests to detect cancer, but sadly not all of them are very reliable, very accurate. There's a great need for improved diagnosis. Treatment is improving all the time. But sadly diagnosis isn't.</s>COHEN: Rob Harris is training dogs to smell prostate cancer.</s>ROB HARRIS: This is Lucy. She's a Labrador crossed Irish spaniel.</s>COHEN: They take urine samples from eight different patients. Now one of the eight patients has cancer, and it is the dog's job to sniff it out. To think that a dog might be able to smell the cancer in that small sample is amazing. So it's number four is the one the dog is supposed to sniff out.</s>HARRIS: That's correct. So Midas will come in, a Hungarian breed. She'll work with my colleague Mark. Would you like to move the position?</s>COHEN: Let's do it all the way on the other side. Catching it at number one is the most difficult because she won't have anything else to compare it to on this round, so this is a real test for Midas. Scientists suspect volatile chemicals evaporate and send off an odor. We can't smell them because we have a measly 5 million sensors in the nose. But dogs have up to 300 million sensors in their noses.</s>GUEST: Midas has got this nose at the end of her face, but she has also got another. It's called the organ of Jefferson (ph) in the back of her throat, and that is screening volatiles as well.</s>COHEN: Any dogs has a powerful sense of smell, but hunter dogs like Kiwi, she's a yellow Labrador, are more easily trained. A recent smaller study found dogs catch cancer with more than 90 percent accuracy. That's higher than many traditional diagnostic tests. We have known for many years that dogs can detect cancer. Are we finally getting to the stage where maybe this will come into actual use in a hospital?</s>GUEST: For the first time I really believe that what the dogs have to use is mainly be used by hospitals. And that doesn't mean that the dogs will be in a hospital, but what the dogs will do will be working in a training center like this, and the samples will be transported to the center where the dogs give the answer and the results is sent back. So yes, I think we're moving forward to the time when the dogs will be used in the diagnostic process, but not by going into hospital cells or sniffing around patients.</s>COHEN: In three years we will know the results of this large study using 3,000 urine samples from National Health Service patients in England. To you think one day dogs like Midas can save lives?</s>GUEST: I really believe that dogs like Midas can save lives. She might have a fluffy coat and a long wagging tail, but she is a very, very, very sophisticated sensor.</s>GUPTA: From dogs to llamas -- you've probably never seen a therapy animal quite like this before.