Can animals really smell cancer in humans?

Cancer research Animal sniffers: Dogs can smell cancer

Whether drugs, explosives or traces - dogs have extremely fine noses: They have 25 times more odor receptors than we humans and these are 10,000 times finer than ours. It is precisely this difference that researchers in the USA have taken advantage of and trained beagles to differentiate blood from people with and without lung cancer. The dogs were almost 97 percent correct. Lung cancer itself is not curable, says study director Heather Junqueira. But the earlier a cancer is detected, the greater the chance of survival. Such a highly sensitive cancer detection test could save thousands of lives, according to Junqueira.

Is that a breakthrough in early detection?

From this study result with four training dogs, two different perspectives can be developed for further research, says Junqueira: On the one hand, one could focus on early detection through the animal's sense of smell in dogs, on the other hand, try to find the biological composition in the blood of cancer patients and to develop an animal-independent test from these results.

Diseases and their invisible "smoke signals"

Apparently, many diseases give "smoke signals". You just have to be able to read these "smell signatures". A similar test has been running at Junqueira's research facility in Orlando since November 2018: in the test series, dogs are trained to sniff out breast cancer in their breath. Incidentally, you are not the first in medicine to rely on dogs. There is a great deal of research around the world that shows that specially trained dogs can smell a low blood sugar level in the breath of diabetics, for example, while others can smell skin or colon cancer, prostate cancer in the urine or urinary tract infections.

The dogs learned to sniff out bacteria in their breath that indicated bacterial pneumonia. Some have been trained to filter out bacterial urinary tract diseases from urine samples. The researchers believe it is possible that dogs can learn Clostridium difficile, Sniffing out in hospital rooms - a stick bacterium that is resistant to heat, dehydration and many cleaning agents and causes severe diarrhea in patients.

Animal diagnoses: pros and cons

At first glance, the diagnostics by the dogs looks impressively simple: a trained four-legged friend smells in an attempt what medical staff can laboriously find out through precise inquiries, observations and time-consuming laboratory analyzes. In addition, without the sick having to undergo laborious procedures. The catch - a dog can learn to differentiate between two possibilities and display them, but each of them is only ever a specialist in exactly one diagnosis.