A dog can accurately detect the early presence of lung cancer by sniffing patients’ breath, doctors in Germany say. While researchers have known for some time that dogs can sniff out the telltale signs of other forms of cancer, this is the first study that proves dogs can reliably smell this particular kind.

This is a breakthrough for lung cancer researchers who have been trying to figure out if there are specific volatile organic compounds associated with the presence of the disease. The dog study suggests that there are.

Researchers at Schillerhoehe Hospital in Germany worked with specially trained dogs who were asked to smell the breath of 220 volunteers. The group included healthy patients, as well as people with lung cancer and chronic obstructive pulmonary disease. The dogs correctly identified 71 positive lung cancer samples out of a possible 100, the researchers write in the European Respiratory Journal. They also correctly identified 372 non-cancerous samples out of a possible 400.