Can dogs detect cancer?

Dogs enjoy a well-deserved reputation as ‘mans best friend,’ thanks to their loyalty, intelligence and enthusiasm for people. However, even so, it would appear that we might have been underestimating the ability of our four-legged friends for quite some time now! An increasing body of evidence is building up to support the theory that dogs can actually detect the presence of cancer in people, and may even prove useful as an early diagnostic aid to identify the presence of a range of additional health problems and pre-cancerous development.If this all seems rather far-fetched and something that should quickly be written off as pseudo-science, this is perfectly understandable; but think again! Even the NHS is currently investigating the possibility that dogs may be able to be used as a tool in the arsenal of cancer detection, and an increasing number of studies and research trials are adding weight to the theory. Intrigued? Read on to find out more!

The Cancer Detection Dog team

The Daily Mail, The Daily Telegraph and various TV programmes have reported on cancer-detecting dogs over the last couple of years, and a Labrador called Daisy has been widely publicised as being consistently able to identify cancerous samples from patients among a variety of other healthy samples. Dr. Claire Guest, who owns and handles Daisy, trained the dog herself after Daisy detected her own breast cancer, and travels widely across the UK with her as part of a Cancer Detection Dog team. So far, Daisy and other dogs within the team have successfully identified the early onset of a range of cancers from medical samples, including breast cancer, bladder cancer, prostate cancer and renal cancer. While all of the dogs in the Cancer Detection Dog team have a significant success rate of correctly identifying or disregarding the appropriate samples, Daisy herself is renowned to have a 100% success rate of accurate detection over a prolonged period of time.

How do dogs detect cancer?

Dogs are well known for their sensitive noses and heightened sense of smell, which is much more advanced than that of people. In its simplest terms, cancer detection by dogs is performed by sniffing out the minute changes in the body chemistry that come about due to the presence of cancer, after being trained to identify the subtle differences between the smell of cancer compared to health. Cancer detecting dogs generally work with samples provided by doctors or hospitals, but can also potentially detect the minute changes in smell that manifest on the skin and in the breath when cancer is present.Dogs are often credited with detecting the presence of cancerous or pre-cancerous cells long before any symptoms manifest that would lead to further testing and a formal diagnosis being made. Research conducted in Germany in 2011 studied four dogs that had been identified as competent scent hounds, and trained them to be able to differentiate the smell of cancerous medical samples from those of healthy people. Within just a few weeks of training, the four dogs were able to accurately identify and differentiate the cancerous samples presented with an effectiveness rating of 71%, a figure that the researchers are confident could be improved upon even further with time.There is also a significant amount of anecdotal evidence from various dog owners that their dogs have identified inconsistencies and changes in their body chemistry through their sense of smell, which has eventually prompted the people in question to get checked out by their doctors and have formal tests and diagnosis performed.

What type of dogs are most likely to be able to detect cancer?

Detecting cancer is essentially the job of a scent hound, and so dogs that have shown an aptitude for scent detection in other fields are those most likely to be able to pick up the scents of cancer that are completely undetectable by people. Breeds such as spaniels, retrievers and German shepherd dogs that are well renowned as a whole for their elevated sense of smell and are often trained for drug detection, bomb detection and in search and rescue are the most obvious choices for use as cancer detection dogs. That said, a dog of any breed or type that displays an aptitude for scent hunting and a willingness to be trained would potentially be able to fulfil the role.

Looking to the future

At the moment, the NHS, cancer research organisations and scent dog handlers are simply working to prove the efficacy of cancer detecting dogs and demonstrate beyond reasonable doubt that some dogs are capable of being trained to detect cancer in the early stages. This means that you will not be able to visit your GP or a local hospital and ask to be checked out by a cancer-detecting dog at this time! However, the results of all of the formal studies and research programmes that have recently been conducted on some dog’s ability to detect cancer have so far strongly supported the theory that some dogs can detect cancer by smell. It is entirely possible that we will start using dogs as part of the process of cancer detection alongside of normal diagnostic protocols in the future.