How Do Dogs Smell Cancer?
Doctors can and do use their sense of smell to assist in certain diagnoses. For instance, it is possible for them to detect aromas in patients’ breath which provide clues to their condition. A doctor might smell alcohol or perhaps the aroma of pear drops which is indicative of a diabetic coma. But the human nose possesses only 5 million sensors. Wouldn’t it be great if it featured 300 million sensors instead? Then doctors might be able to smell cancer.
Dogs’ noses do feature 300 million sensors and they also benefit from an additional smelling device called the Jacobson’s organ. Dogs have an amazing sense of smell and can, Indeed, smell cancer in humans.
But how exactly do they do this?
Dogs and Volatile Organic Compounds
Human breath, urine and faeces contain trace amounts of chemicals from our metabolism which are known as Volatile Organic Compounds (VOCs). Studies have shown that the type and – composition of these VOCs can be a strong indicator of diseases including cancers, asthma, sleep apnoea and C. difficile infections.
Dogs can detect minute concentrations of these VOCs. Studies conducted in 2011 and 2012 demonstrated that dogs could detect colon cancer in human faeces and lung cancer in breath samples.
Now, there is to be a significant trial undertaken with the aim of discovering how efficient dogs are at detecting prostate cancer in urine samples. This has been initiated by Medical Detection Dogs, the charity which trains canines to identify human disease. The full study has been preceded by trials which have shown dogs to have a 93% success rate in identifying the cancer. This is a higher rate than that achieved by most laboratory tests and so the dogs’ ability has big implications.
At the moment, the Prostate-Specific Antigen (PSA) test is used in laboratories to determine whether men may have prostate cancer. But this type of test delivers many false positive results leading to men being referred for further investigations that are unnecessary. This negatively impacts the budget of the National Health Service. It is clearly even worse when the test fails to pick up on the presence of cancer.
Secondary Cancer Tests
The full study will be conducted by Milton Keynes University Hospital, Bucks. If it is successful, Medical Detection Dogs hopes that the screening provided by the dogs could be offered as a second test to back up the standard laboratory tests. The dogs could pick up on cancers missed by the lab and so facilitate earlier diagnosis and treatment. This could mean a much better outcome for some patients. The dogs will also identify false-positive results which will save patients from anxiety and the Health Service from the cost of unwarranted investigations.
The early detection of cancer can be problematic and Britain has one of the worse rates of early detection in Europe. The dogs could be game changers.
It could be that even your dog is able to smell cancer. There is a great deal of anecdotal evidence to suggest that pets have picked up on their owner’s illnesses before the people concerned have been aware of any problems.