Tests conducted by researchers at the university of Kyushu in southern Japan indicate dogs can detect early stage colorectal cancer.
The findings show that cancer cells that circulate around the body emit odors that are detectable by dogs. The researchers say this could lead to the development of tests that can detect intestinal cancer at a very early stage before it has a chance to spread.
Previous evidence suggests dogs are capable of identifying breast and lung cancer too. The researchers' findings have been published in the online edition of the British journal Gut.
In the study, a specially trained Labrador spent several months conducting 74 sniff tests. Each test was made up by five breath or stool samples, only one of which was known to contain cancer cells.
The samples came from 48 persons diagnosed with intestinal cancer as well as 258 volunteers who were cancer-free or who had had cancer in the past.
The dog was able to identify the cancer samples with a success rate of over 95 percent. The highest score rate was for samples from people with early-stage cancer, according to the findings. Samples from smokers or individuals with other intestinal illnesses did not pose a problem for the dog.