Cancer-Sniffing Dogs

 New from the Journal of Clinical Oncology: "Canine Olfaction Combined With Bayesian Modeling for Multicancer Detection From Breath Samples: A Phase II Study in India."

Of all the ways to detect cancer, the best has to be dogs who can somehow smell it.

(I know, I know -- the "best" is the cancer detection test that works the best at detecting cancer. But a colonoscopy doesn't love you unconditionally. That would make a great slogan on my Lympho Bob t-shirts, if I actually had any for sale.)

I'm fascinated by cancer-sniffing dogs. This study took place in India. The idea is that training dogs to sniff cancer might be especially helpful in what the authors call "low and medium income countries."  Cancer detection can be very expensive. Dogs will work for very little -- a couple of biscuits and a pat on the head.

Seriously, though -- as the authors point out, dogs have been trained to sniff cancer for 30 years. The first known cancer-sniffing dog was standard schnauzer named George, who was able to detect skin cancer. Studies that looked at cancer-sniffing dogs have mostly been small, and have taken place in higher-income countries. 

For this phase 2 clinical trial, 3275 patients were enrolled. 1773 were used in training the dogs, and 1502 in the actual testing. For the tests, patients breathed into cotton surgical masks, which were then stored at -20 degrees Celsius. 283 of the patients actually had cancer -- one of seven types (head and neck, breast, lung, gynecologic, upper and lower GI, and genitourinary cancers -- there were no blood cancers among them). Each mask was sniffed by three different dogs, and the collective results were combined.  The dogs correctly detected about 90% of the samples with cancer, and about 91% of those without cancer. They were just as accurate with stage I and II cancers as with later stage cancers -- important for those cancers where early detection can increase survival.

You might not have access to the JCO article, so you can read more about it here. The company that did the testing is called Dognosis. They are working on a system that will use AI to help pick up the signals that the dog is giving. (If you've ever trained a dog to do any kind of scent work, you know it can be hard to pick up their signals on your own.)

And if you're wondering what breeds of dogs were involved, they were four Beagles, one Labrador, one Labrador-Indie mix, and one Dutch Shepherd-Belgian Malinois mix. There was less than 2% variation between the dogs, meaning it really didn't matter which dog was doing the sniffing. They all did equally well in detecting the cancers. 

The reason I find all of this so fascinating is because I have owned two standard schnauzers -- like George, the first cancer sniffing dog. Our first, Strudel, was about a year old when I got my cancer diagnosis. If she noticed anything, she didn't let me know. Our current dog is Katara, who is 5. She didn't say anything about either of my skin cancers. Maybe I just haven't been listening very well.

 

We've actually done some scent work training with Katara, just for fun. And we've learned a lot about how sensitive dogs' noses are -- about 10,000 times more sensitive than a human's nose. Out trainer explained it to us this way: when we humans smell a chocolate cake, we smell a chocolate cake. But a dog can smell the flour, the eggs, the sugar, the cocoa, etc.  Their noses are really amazing instruments.

So if you have a dog, give them an extra hug today on behalf of all the work that other dogs are doing for us.