Can Dogs Smell Cancer?

Dog Licking Owner's Face

What is all this hype about dogs smelling and detecting cancer? And even at its earliest stage? Is it true? Yes, dogs can smell cancer because of their excellent sense of smell.

Olfactory cortex dominates a dog’s mind in opposition to our dominant visual cortex. Dogs are guided by the scent rather than the sight of their targets, for example, dogs cannot distinguish between green and red objects but can smell the target object.

Studies show that dogs can smell the missing amino acids in their foods; and may skip meals1. Then, how can we doubt their cancer smelling abilities?

Olfactory Cortex of Dogs:

The olfactory cortex in dogs is 40 times bigger than that of humans. The cortex has 125 to 220 million smell receptors that are highly reactive to different kinds of smells. So, science backs the idea well by revealing that the smelling capacity of dogs is about 100,000 times better than humans.

So, if your dog has started licking you all of a sudden, find out why your dog licks you at a particular spot. It might be undetected cancer that’s eating you inside.

How Dogs Detect Cancer?

Cancer cells release metabolic wastes that are different from those released by healthy cells. Surprisingly, dogs can smell the minor difference even at the earliest stage of cancer. The chemical traces are detected by dogs in ‘parts per trillion’.

Different researchers have shown how dogs can sniff cancer in human breath, human urine, and skin lesions. There are various types of cancers that the dogs can sense in humans most quickly.

According to various researchers, dogs have been able to detect skin cancer (melanoma), prostate cancer, ovarian cancer, bladder cancer, bowel cancer, and lung cancer.

Can Dogs Help Cancer Researchers?

Dogs provide an extraordinary help in detecting cancer after a little bit of cancer detection training. Cancer researchers are thinking to utilize the dog’s ability to sniff cancer by training them and keeping them in the loop of patient care.

Some researchers recommend that trained cancer-detecting dogs should be confined to laboratories that have gas chromatographers to separate specific cancer compounds that are easily identified by dogs.

Besides this, recent advancements include the development of a breathalyzer that changes color when it comes into contact with certain cancer compounds present in human breath. Along with that, electronic noses are being introduced in medical science laboratories to detect cancer.

What does the research say?

Let’s have a look at various researches that have been done in the field!

  1. A 2003 study at Pine Street Foundation conducted by Michael McCulloch, an acupuncturist, showed that dogs can identify lung cancer with about 99% accuracy and breast cancer with 88% of accuracy.2
  2. A study, published in British Medical Journal, was conducted to find out that whether dogs can detect bladder cancer by sniffing urine odor. The results showed about 41% accuracy of the trained dogs.
  3. Dr. Armand Cognetta, melanoma expert at Tallahassee, trained a dog named George to detect skin cancer. George was able to detect melanoma with 99% accuracy; he could differentiate between malignant and benign lesions in skin cancer patients.
  4. A 2011 study revealed that dogs identified lung cancer dogs with a 93% specificity of patient’s breath samples.3
  5. Research in Milan at Humanitas Research Hospital was conducted by providing the dogs with a total of 320 urine samples of patients with prostate cancer and 357 urine samples of patients without cancer. Dogs were able to show 98% of accuracy as a result.4


After all these pieces of evidence about the accuracy rate of detecting cancer, it’s for sure that dogs can detect cancer. Their olfactory bulb is their greatest guide-probably that’s the reason they love treats for training.


Author Bio:

James Shore is a part-time dog-trainer and dog behavior consultant. He is a professional freelancer with years of experience in dog training. He is interested in finding out fun ways to handle dog behaviors, specifically, Labradors to help dog-owners enjoy their companions at all times. His pet-passion led him to develop to help people.

Posted in Can Dogs Smell Cancer and tagged , , , , .