Dogs Can Smell Fear But Can't Detect If You Have Lung Cancer

A new research suggests that despite dog's uncanny ability of detecting illnesses, identifying lung cancer is not one of them. According to the study published in Journal of Breath Research, the results of the study contrasted with other previous studies related to canine scent detection ability.

Researchers trained six sniffer dogs with 150 breath samples for six months beforehand to prepare them to a test that will determine if they are good at detecting lung cancer. The dogs are tasked to identify correctly which of the 122 volunteer patients have lung cancer. These patients were recruited by researchers from Krems University Hospital and several other institutions. Out of 122 patients, there are 29 who are diagnosed with the disease but haven't received treatment while 93 of them show no signs of it.

The volunteer patients will give breath samples while six dogs will sniff the samples and try to identify if such sample is from a lung cancer patient. To avoid subjective biases, the experiment was done in a double-blinded method.

The results, however, are not as good as it did with other canine scent detection studies. Though the dogs were able to detect 79 percent of those with lung cancer correctly, they were only able to detect 34 percent of patients who do not have lung cancer.

The researchers, however, are not disheartened. They take the results as a learning experience and still believe that one day, dogs can still detect lung cancer effectively by setting effective protocols. They are also keen to knowing what could have affected the results.

According to Klaus Hackner, co-author of the paper, the "true double blind situation" must have brought stress to both dogs and their handlers. As in any sniffing detecting experiment, success and rewards are as important.

Hackner also said that the disparity of the results is not a detection issue as dogs are known for their effective ability of sniffing out bombs and do rescue search. However, unlike analytical instruments used to detect diseases, dogs are subjected to boredom, limited attention span, fatigue, hunger and external distraction.

The study also poses the limitations of the dogs in doing "complex and psychologically demanding tasks". Other than diseases, dogs can also detect our fears.