Can dogs detect cancer by smell?
Just read an article about dogs can detect cancer by their astounding sense of smell. The stories are similar, family pets worrying or persistently sniffing at a certain area on their owners, which subsequently turns out to harbor a tumour. The idea has been around for a while, you can find articles and reports on the internet such Cancer Research UK, BBC new, CNN and all over the world.
I have two dogs, one Dalmatian and one toy Poodle. They are really good at smell, they can find their foods no matter where I hide them. Well actually our furry four-legged friends have a range of impressive skills, they can find survivors from ruins, lead the blind, detect drugs or dangerous goods from smugglers. But can they sniff out cancer? I found some scientific basis behind this idea. Have a look.
All smells – from the pleasant aroma of freshly cut grass to the whiff of durian – are due to molecules diffusing in the air, given off by whatever is causing the pong.
These volatile molecules are detected by scent receptors in the noses of humans and animals, sending signals to the brain which then interprets the smell. Dogs have an astounding sense of smell, because their noses are packed with many times more scent receptors than humans have.
And we know that some tumours produce unusual volatile molecules, such as lung cancer, kidney cancer, breast cancer, and melanoma which are presumably being picked up by the dogs in the stories mentioned above.
But does this mean that we should have “cancer sniffer dogs” in every GP surgery? I think the answer is negative. The idea is nice, I hope my dogs will let me know as soon as I have cancer, but it’s simply not realistic to transfer this to a clinical setting. First of all, there are the practical considerations. Dogs would need to be housed, fed and trained, and would not be able to work for more than a few hours at a time for the sake of their welfare. And there’s also the chance that they may be confused by other scent molecules on the breath or in urine, such as garlic, asparagus, tobacco, alcohol or other pungent foods. More importantly, it’s still not clear from the research that the dogs are picking up specific molecules originating from a tumour, or are just picking up molecules associated with more general illness.
Dogs are also – obviously – unable to tell doctors exactly which molecules are faulty in an individual’s cancer – information that can be obtained using molecular diagnostic techniques (“electronic nose”). This is important because such information is increasingly being used to tailor treatment to an individual’s cancer.
And I don’t think every dog can sniff cancer, my dogs had no unusual behavior before my father was diagnosed kidney cancer. Maybe they smelled something, but they just don’t know what is that smell.
Introducing the electronic nose
Although they don’t have furry coats, there are “electronic noses” that can pick up the volatile molecules produced by cancer cells with greater accuracy than a real life cold, wet one. This kind of technology is being tested in a range of cancers, including breast and lung.
It’s still early days for electronic noses, and we need to see a lot more research to make sure the machines are accurate and reliable at detecting cancer. But once the technology has advanced further, it’s likely that they will have wide applications for detecting many different types of cancer. And they won’t need feeding or walking either.
although these small research studies show that dogs could have the potential to pick up cancer, their accuracy is questionable. It’s important to have a test that is as reliable and accurate as possible in the case of tests for cancer – although, of course, no test is ever 100 per cent infallible. This cuts down on the chance that cancers will be missed (false negatives), or that a diagnosis of cancer will be wrongly made (false positives).
reference: http://stanford.wellsphere.com
I recently lost my mother ot renal...
Everything dynamic and very positively!
Rufor
[Reply]