Can Dogs Smell Cancer in Humans? Vet-Verified Facts & FAQ

It’s been thought for centuries that dogs can smell illnesses, diseases, and even oncoming storms. However, there have also always been people who think that those are just old wives’ tales. Dogs do have a keen sense of smell, though, so it’s not a surprise that they can sniff out things that we can’t.

So, can dogs smell cancer? Yes, according to a 2006 study,1 canines can sniff out and detect cancer in humans. But how can they do this? We answer that question and others here.

Can Dogs Sniff Out Cancer?

Studies have shown that dogs can sniff out certain types of cancer in humans.2 Cancer, like other diseases, can leave odor signatures on a person’s body. There is evidence that volatile organic compounds (VOCs) are produced by certain diseases and that dogs can smell these.

Depending on the type of cancer the person has, a trained bio-detection dog can detect VOCs when exposed to these:

• Breath
• Skin
• Urine
• Feces
• Sweat

Canines are able to detect these smells, so if they have been trained to do so, a dog can alert their handler that there is a problem.

What Type of Cancer Can a Dog Detect?

While all the types that they can smell are still being researched, dogs can smell the following cancers with a significant amount of accuracy.

• Malignant melanoma
• Colorectal cancer
• Lung cancer
• Ovarian cancer
• Prostate cancer
• Breast cancer
• Bladder cancer

How Can Dogs Smell Cancer?

Tumors produce VOCs, and these are released into the breath, sweat, urine and feces. It is thought that the dog’s sensitivity to these smells enables them to smell cancer in some people or samples in a laboratory setting. There is also work being done into the theory that they can smell a change in a person’s gastrointestinal biome (natural bacteria) that seems to be involved in cancer.

While cancer-detecting studies have shown promising results, dogs can’t sniff out cancer in patients with 100% accuracy. So, don’t be ready to give up medical testing in favor of a canine’s nose just yet.

What Other Things Can Dogs Smell?

Dogs have a keen sense of smell, over 10,000 times better than humans, so they can easily smell things that we can’t. But can dogs smell other diseases? Yes, they can!

1. Oncoming Seizures

Medical alert assistance dogs can be trained to sense when their handlers have a seizure coming on. The dog can detect a change in their owner's scent up to 45 minutes before a seizure occurs and alert them so they can be safe.

2. Bacteria

Dogs can be trained to smell specific types of worrying bacteria and ignore those that are beneficial. In the future, it is hoped that this will help detect serious bacterial infections early and reduce antibiotic resistance.

3. Diabetes

Specially trained dogs can alert their human companion to dangerous changes in blood glucose and even get help for the person or bring them their medications. These service dogs improve the quality of life and health of their lucky humans.

4. Malaria

Scientists are always looking for reliable, fast, cheap, and easy ways of providing good healthcare. Malaria is a devastating illness spread by mosquitoes and is especially common in large parts of the African continent. Recent and ongoing work has shown that dogs can be trained to smell malaria-infected socks with a promising accuracy of 73%.

Conclusion

While dogs can smell cancer in humans, medical testing is still essential if you’re suffering from an illness. Canines can detect several types of cancer, but not with 100% accuracy. There is still a lot to be learned and improved when training dogs to detect cancer, but strides are being made in this exciting research every day.

Featured Image Credit: rfranca, Shutterstock