Carlos Solis
There’s growing scientific evidence that dogs can spot cancer — but only when the animals are specially trained.
What the research shows
In a number of studies, researchers analyzed breath, urine, and other biological samples from patients with cancer. The animals were able to detect several cancers, including:
- lung cancer,
- colorectal cancer,
- prostate cancer.
In some cases, trained dogs outperformed standard laboratory tests on detection measures and produced fewer false alarms.
Why dogs can do this
Researchers think dogs’ sense of smell detects volatile organic compounds produced by malignant cells. Those compounds enter the breath or urine and alter the chemical signature, which allows a trained dog to distinguish samples from sick people versus healthy ones.
A review of existing studies cautions that researchers still don’t know whether dogs detect cancer early enough to be clinically useful. Large, controlled trials are necessary to confirm the accuracy and reproducibility of these findings.
A large study in the U.K. is testing whether dogs can detect cancer from breath samples of 1,500 women. The results should provide clearer answers about the method’s practical use.
This article is based on BBC Science Focus.
