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Can dogs be trained to detect the smell of cancer?

September 6, 2014 at 11:42 AM EDT
For the past few decades, researchers have been exploring the possibility that cancer, possibly created by the growth of tumors, actually has a particular odor -- and dogs can pick up on that smell. Some doctors believe this area of research may lead to more efficient screening methods and cancer treatment procedures. Special correspondent Dr. Emily Senay reports.

EMILY SENAY: You’ve seen them on the streets helping the blind, at airports and train stations sniffing for explosives and at the scene of earthquakes searching for survivors. But ever since her family got a Doberman puppy, this 55 year old retired magazine editor from New York’s Staten Island believes there may be another way for dogs to save lives.

One night in the spring of 2011, a couple of weeks after getting a new puppy, Diane Papazian noticed her dog Troy behaving strangely.

DIANE PAPAZIAN: So, he’s in bed with us, and he is in between my husband and myself, and– so, his head is right here. And he is nuzzling up against my left side, and he keeps nuzzling, and he’s nuzzling, and he’s not stopping. And I’m thinking, what in the heck is going on with this dog? Cut it out, you know, that’s so annoying. What are you doing?

And– he kept doing it persistently, like it wasn’t just once or twice, it was for a few minutes that he kept nuzzling. So finally I said, what in the heck is he doing? So, I started to itch, because I’m highly allergic, and that’s when I felt the lump.

EMILY SENAY: Just days after discovering the lump, doctors found a tumor three centimeters long. Diane was diagnosed with an aggressive form of stage two breast cancer. She had gone for a mammogram six months earlier which was clear and wasn’t due for another mammogram for another six months.

EMILY SENAY: When you went to the doctor, did you say, you know my dog sort of alerted me to this?


EMILY SENAY: And what did they say when– when they heard you– heard your story?

DIANE PAPAZIAN: Well, I don’t think– I think they kind of partly thought I was a little crazy. But I think that they– probably have heard enough stories about dogs and their– very keen sense of smell that they weren’t– completely surprised.

EMILY SENAY: Diane’s story might not be so crazy after all. For the past 25 years, cancer researchers have been exploring the possibility that cancer actually smells like something—and that dogs can detect that smell.

EMILY SENAY: The idea of dogs smelling cancer makes perfect sense to Doctor Cindy Otto, a veterinarian with a doctorate in veterinary physiology. Otto started the Penn Vet Working Dog Center at the University of Pennsylvania in 2007. She thinks dogs could be picking up on the changes in odor researchers believe are created by cancer cells.

CYNTHIA OTTO: It makes sense that they could change the odors that are released from that person. And a dog, with their extremely sensitive sense of smell, might be able to pick up that change.

EMILY SENAY: At the Penn Vet Center, researchers are testing that idea. A team of four dogs like Tsunami, a German Shepherd and Ffoster, a Labrador Retriever are being trained to detect blood samples from ovarian cancer patients. Ovarian cancer kills more than 14,000 women in the US each year and is especially hard to detect in early stages. The dogs are rewarded for sitting down after identifying which of the samples contains cancer.

Researchers like Otto started investigating the idea of dogs smelling cancer after hearing stories from people like Diane Papazian.

CYNTHIA OTTO: People would report that their dog was acting differently. And they went to their doctor and they found out they had cancer. Or the very first case was a dog that was biting at a mole. And that person went in and found out that it was melanoma.

And so just taking that, the stories that people have, and realizing there’s some really important information in those stories.

EMILY SENAY: Otto acknowledges the research is preliminary- her study is still ongoing and hasn’t been submitted for peer review. But she says the early results have been exceptional.

EMILY SENAY: When you say exceptional, what does that mean? How accurate are they?

CYNTHIA OTTO: About 90% of the time these two dogs are telling us, “That’s the cancer sample.” And the other samples that are out there, whether it’s from a normal patient or from a patient with– benign ovarian disease, they’re like, “Nah, it’s not that.”

EMILY SENAY: It’s not just the University of Pennsylvania. At a meeting of the American Urological Association in May, a group of Italian scientists from Milan presented the results of a study claiming a 98 percent accuracy rate with two dogs in detecting prostate cancer from urine samples. That study has yet to go through scientific review for publication, but researchers are hopeful it will eventually lead to an earlier and more accurate screening tool for prostate cancer.

GARY SCHWARTZ: The holy grail of oncology has been to try to develop a test, either in the blood or the urine or some bodily fluid that would allow us to detect cancer at an early stage.

EMILY SENAY: Doctor Gary Schwartz is the head of oncology and hematology at Columbia University Medical Center. He’s impressed by the results from the Italian study- but has some doubts about the 98% detection rate.

GARY SCHWARTZ: I am a little skeptical on the outcome reported in this particular abstract from the Milan group.
Now maybe prove I’m wrong. I mean, that’s the scientific part of me. I’m– but being a scientist as well as a physician, I think we always have to question until we see all the data, and all the information, we shouldn’t make any definitive conclusions about any finding. And at this point and in my analysis of the information we have, it’s still an open question how good the dog really is.

EMILY SENAY: Even if the dogs can be trained to detect cancer, how useful will that turn out to be?

EMILY SENAY: Do you see the day when dogs are used in a practical way to screen for cancer?

GARY SCHWARTZ: I would say not. I really can’t envision a dog si– sitting in a clinical laboratory at a desk or in front of a series of urine samples saying, sniffing around, saying, “Oh, this one is and this one isn’t.” I just– The dog gets distracted on that sample, and it’s called maybe negative when it could be positive. So I think we’re better than that. I think we have better technology that we can use now to find whether a patient has– a cancer.

EMILY SENAY: Schwartz says there are more promising prospects for early detection such as tests that find cancer DNA in the blood, but he acknowledges there may be something to the science of using dogs to detect cancer.

GARY SCHWARTZ: Yeah, I suspect there is an odor– and that’s what the dogs are reacting to. Dogs have increased sensitivity. So the dogs are– are showing us something, they’re leading us down the path in which we can apply our own scientific methodology to identify what’s in the urine to which they are finding offensive, and to which they’re reacting to. And this in itself could be a significant advance.

EMILY SENAY: And– we spoke with– the head of hem-onc at Columbia. And he said, “Gosh, I don’t see the day when dogs are gonna be working– sniffing samples, detecting cancer.”

CYNTHIA OTTO: I think that it’s good to have skepticism. I think what we’re learning is that not all dogs can do this. It takes special training. But I also agree completely that dogs are not gonna be in the hospital laboratories, sniffing samples. Our goal with the dogs is to help direct where– how we can build a better screening tool.

EMILY SENAY: Doctor Otto acknowledges that training cancer detecting dogs is time consuming and expensive at more than thirty thousand dollars a dog each year- and dogs can only identify a limited number of samples each day. But she sees her research eventually leading to a more efficient screening tool.

CINDY OTTO: The dogs themselves probably aren’t gonna do the final job. They’re helping us design the tool that will then become the screening tool. Something that is more automated, something that is inexpensive and can screen thousands of women, millions of women a year.

EMILY SENAY: That’s where Doctor Charlie Johnson comes in. He’s a physicist at the University of Pennsylvania using nanotechnology to develop what amounts to an electronic nose capable of smelling cancer. So one day his device might be programmed to measure the gases and compounds emitted from tumors that Doctor Otto’s dogs are smelling.

A.T. CHARLIE JOHNSON: Our idea is to create a little device that can actually smell the vapors in the air and use it to smell the vapors that are emitted by blood samples and to tell which people have cancer based on that information.

EMILY SENAY: Can your robotic nose beat a dog’s nose yet?

A.T. CHARLIE JOHNSON: The best we can hope for I think will be to equal the dog’s nose. The dog are amazing. I mean, I think one thing we have done is we have demonstrated our ability to detect– a very small amount of a chemical that people cannot smell at all.

EMILY SENAY: Johnson hopes to create a cancer detecting device as small as an iPhone that could be in every doctor’s office, but says they’re years away from that goal. But the dog study gives them hope that getting sniffed for cancer by an electronic sensor one day could become a routine procedure.
After a double mastectomy and chemotherapy, Diane Papazian is cancer free today, and she says that’s all thanks to Troy.

DIANE PAPAZIAN: I always say that had it not been for Troy, I don’t know if– I would be here today, or what the situation would’ve ended up really turning out to be.

EMILY SENAY: You believe that?

DIANE PAPAZIAN: I know that he was trying to tell me something in his own little, sweet way.