4 min read


Can a Dog Smell Cancer?



4 min read


Can a Dog Smell Cancer?


You already know that your dog has a gifted nose - they can smell the treat bag open from across the house, they always know when you pop open the shampoo bottle for bath time, and they never fail to come running when bacon is cooking. But how remarkable is their nose, really? 

Did you know that dogs' noses are so gifted, they're actually able to sniff out cancer - even in its earliest, nearly-undetectable stages? Dogs have about 25 times more smell receptors than people do, making their smelling abilities about 100,000 times more capable than ours. So, with that knowledge, it should come as no surprise that dogs are able to sniff out cancers before we even know we have them. 

If you want to know more about how your dog can sniff out cancer, how dog's noses work, and what signs you should look for if you think your dog might be an overly-exceptional sniffer, read on! We've constructed the ultimate doggo-nose guide to explain to you how your pup's snout really works. 


Signs Your Dog Might Be Able to Sniff Out Cancer

Because dogs are able to smell so well, they're able to sniff out a number of medical conditions and give their people a heads up if something is wrong. Dogs can smell in parts per trillion. Think about it; if there's one cc of blood that's been diluted into 20 Olympic-sized swimming pools, your dog can smell that blood, no problem. 

Cancer cells have a distinctly different smell than regular, healthy cells, so it makes sense that your dog would be able to detect a change in the odor. Your dog will likely know something is wrong with you before you do (likely a lot earlier than you will). 

If you're suspicious that your dog might be trying to tell you something (like that he's smelling cancer), keep an eye out for some specific signs. For example, your dog might sniff certain spots on your body more often than others, or show an affinity for a specific spot on your body. Your dog might also begin obsessively licking a certain part of your body, potentially where they might detect a cancerous smell. 

Keep a lookout for uncharacteristic behavior, too. Diseased or cancerous smells distress dogs, and they'll become even more distressed and put out if you ignore their requests for a response. If your dog becomes more vocal, agitated, stressed out, or anxious while they're smelling or licking you, something might be off.

Body Language

Keep an eye on your dog to see if they are giving you these body language cues:

  • Growling
  • Alert
  • Barking
  • Guarding
  • Cowering
  • Ears Drop
  • Head Turning
  • Head Bobbing

Other Signs

Here are a few more signs your dog might be giving you to let you know they smell something funny:

  • Obsessive Licking
  • Uncharacteristic Anxiety
  • Frantic Behavior
  • Nervousness

The History of Dogs Smelling Cancer


We'll get into the science behind your dog's superhero nose in our section below, but it suffices to say, your dog can do wondrous things with that snout of theirs. Research suggests that dogs' noses are so gifted, they can detect cancer in its earliest stages. In fact, in Berlin, a group of researchers trained dogs to detect the presence of various cancers (including ovarian, bowel, cervical, bladder, skin, prostate, and lung cancer). 

In one specific case, Lucy, a Labrador Retriever mix from the UK, was trained over the course of seven years to sniff out various types of cancer. Over time, she's been able to detect cancer correctly more than 95 percent of the time (better than some lab tests that are used to diagnose the disease). She's now part of one of the largest clinical trails of canine cancer detection called Medical Detection Dogs, a British Organization. 

The Science Behind Dogs Smelling Cancer


To understand a dog's smelling capabilities,  it's important to first understand how doggo noses work. Dogs have about 25 times more smell receptors than humans do. To put it bluntly, they can smell about 100,000 times better than we can. 

Because of this, their brains work a little differently. Instead of dog brains being dominated by the visual cortex, the olfactory cortex leads brain function. For good reason, too - a dog's olfactory cortex is about 40 times larger than a human's. But how does this equate to a nose of cancer-sniffing quality? 

Studies suggest that cancerous cells release different metabolic waste products than healthy cells (in humans) - different waste, different smells. This means your dog, with their superhero nose, can tell the difference between those smells. In fact, the difference in smell is so significant, your pup can identify cancer in its earliest stage. Because of this, dogs have been trained to sniff out cancer in patients. 

Training Your Dog to Smell Cancer


Training a dog to detect illnesses, including cancer and other diseases isn't necessarily something you can do from the comfort of your own home. Likely, you'll have to train your dog with a research organization or an animal behaviorist. 

Scent detection will involve a reward system to provide motivation for correct identification, hundreds of samples collected using rigid standards in a clinical setting under strict guidelines, and organic compounds produced by cancer cells that occur in combination with other organic compounds present from the metabolism of non-cancerous cells in the body. 

You'll need to make sure your dog is already trained to have a calm, focused demeanor, a cool, collected temperament, and is reliable under pressure. 

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By a Great Dane lover Hanna Marcus

Published: 03/16/2018, edited: 04/06/2020

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