I recently stumbled across this study which I found absolutely mind blowing. Here’s how researchers did it.

They trained 5 dogs by using a food reward system to recognize, by scent alone, the exhaled breath samples of 55 lung and 31 breast cancer patients from those of 83 healthy controls; once the dogs were trained to do this, their accuracy was just amazing. Among lung cancer patients and controls, the canine sensitivity compared to that of biopsy results was 0.99 (95% confidence interval), and the overall specificity was just as good. Among breast cancer, the results were slightly lower, at 0.88 (95% CI, 0.75, 1.00) and specificity 0.98 (95% CI, 0.90, 0.99). These results were remarkably similar for all stages of the disease, which means they can catch it in the initial stages as well.

The conclusion? Dogs can be used to identify breast and lung cancer with a 95% accuracy, at a fraction of a fraction of the costs of a biopsy. The dogs were trained in a matter of weeks, not even months, so this could actually work as a practical method.

“This pilot work using canine scent detection demonstrates the validity of using a biological system to examine exhaled breath in the diagnostic identification of lung and breast cancers. Future work should closely examine the chemistry of exhaled breath to identify which chemical compounds can most accurately identify the presence of cancer”, the study concluded.