Asked by: Mike Shelby, Reading
Stories about dogs warning their owners of early signs of cancer have been circulating for years. Now hard scientific evidence is emerging to back the idea – at least for trained dogs. Studies involving dogs exposed to samples of breath, urine and other body fluids from cancer patients suggest they can detect the presence of lung, colorectal and prostate cancer, among others. In some cases, the dogs outperform standard lab tests, achieving higher detection rates and fewer false alarms.
Researchers believe the dogs’ highly refined sense of smell can detect the volatile organic compounds produced by malignant cells. However, a recent review of the evidence cautioned that it’s still unclear whether the dogs can pick up signs of cancer early enough to be useful. More research is needed, and a major UK trial of the ability of dogs to detect breast cancer in breath samples from 1,500 women is currently underway.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.