Can Dogs Smell Cancer?

November 10, 2020 4 min read 0 Comments

A brown sharpei dog sniffs a person's leg as they pet it

Dr. Sara Ochoa author of Can Dogs Smell Cancer?

Dogs are incredible at helping us with many different tasks, such as seeing-eye dogs, rescue people, and even detecting bombs. Many people may wonder if dogs can be used as early detection for cancer in humans. Dogs have a wonderful sense of smell, and this would make people believe that dogs can do great at smelling out cancer. Recent studies have shown that some dogs may be able to detect cancer in their owners, but this may not translate to all people.


Can Dogs Smell Cancer?

Some have been found to be able to pick up on it, but it isn’t exactly well researched. Dogs can quickly and easily pick up on detecting a change in smell, such as food being prepared. At the same time, cancer is when cells are rapidly changing and may give off a scent that some dogs can smell. One study gave dogs different urine samples to smell. Some of these had bladder cancer. Others were normal. This research showed that dogs only detect cancer accurately, only 40% of the time. This does not make them a reliable diagnostic tool in early cancer detection.

While there are single cases of dogs detecting this chemical change in their owners, it is not a trainable skill at the moment. Many dog trainers and behaviorists are working on training dogs to be able to do this task, so hopefully, one day, your dog may be able to alert you of early cancer.


How Do Dogs Smell?

Dogs have up to 300 million olfactory receptors present in their nose. This is compared to only about six million people. This is 40 times more sensitive than our noses! This makes them very keen smellers. This is why dogs are commonly used in search and rescue, as they can trace a human scent for miles.


How Does this Help Them Smell Diseases?

This keen sense of smell can help your dog detect even the slightest change in a scent that cancer cells may be giving off. Research has found they can even smell the very slight trace of disease.


Can All Dogs Smell Cancer?

Not all dogs can smell cancer.  Just like with working dogs, they need a lot of training.  The dogs that are being trained to detect cancer are only being trained as a trial process.  More research is needed to be done to determine if dogs can actually be used with reliable results.


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How do dogs alert people that they have cancer?

There are accounts of dogs who have alerted their owners that they have cancer. These dogs would act very differently. They may have pawed and their chest or stomach.  Many would bark and run and hid when they detected cancer.  Many dogs will paw or even bite at cancerous growths on their owners.


Will Doctors Use Dogs to Sniff Out Cancer?

It is very unlikely that a dog will be used as the only way to detect cancer.  Especially since there are certain things that a dog may smell that would alert you that you may have cancer when, in fact, that you do not.

It has not been determined whether dogs can be reliably trained to smell cancer.  It would be very difficult to train a dog to communicate what they have smelled without further testing accurately.  If dogs do manage to be trained this way, it will be a long time before this is made practical

An alternative being researched is an ‘electric nose.’  These electronic nosescan pick up the unstable molecules that are produced by cancer cells with better accuracy than your dog.  This type of technology is being tested in many different types of cancers, such as breast and lung cancer.  

It is still very early to tell if electronic noses will be readily used.  There still needs to be a lot more research to make sure that these machines are accurate and reliable at early cancer detection.  This is one technology that has advanced further than any other of its kind.  It is very likely that they will have wide use for detecting many different types of cancer. Electronic noses have the same job as a dog’s nose but would give doctors more reliable and consistent feedback.  

If your dog is trying to alert you of something and you cannot figure out what they are trying to tell you, continue to investigate.  They may be alerting you that you may have cancer.  While dogs are not a very reliable indication that you have cancer, they may be used more in the future.  Electronic noses with more development and testing may be the next device that is used in human medicine to alert people that they have cancer.

Dogs can do amazing things, and if we can teach them to detect cancer early, this could possibly help extend the life of their owners.


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Meet The Author 

Dr. Sara Ochoa DVM author of Can Dogs Smell Cancer? Why Is My Dog Itching So Much

Dr. Sara Ochoa DVM

Since she was a little girl, Dr. Ochoa knew that her dream was to become a veterinarian. With a tremendous passion and love for animals, she is now a great source of knowledge for others. Dr. Ochoa lives happily with her husband Greg and her babies: Ruby the Schnoodle and Bam-Bam the bunny.