Dogs can be trained to sniff out early signs of lung cancer on patients' breath, German scientists said Thursday.

Researchers discovered that dogs trained to pick up on volatile organic compounds linked to the presence of cancer correctly identified 71 percent of those people with the disease and detected 93 percent of patients who did not have lung cancer.

The canines also were able to distinguish between chronic obstructive pulmonary disease, which is linked to smoking, and the patients with tumors, according to scientists at Schillerhohe Hospital in Stuttgart, southern Germany.

"In the breath of patients with lung cancer, there are likely to be different chemicals to normal breath samples, and the dogs' keen sense of smell can detect this difference at an early stage of the disease," according to Dr. Thorsten Walles, the study's lead author.

Writing in the European Respiratory Journal, he added, "Our results confirm the presence of a stable marker for lung cancer. This is a big step forward in the diagnosis of lung cancer."

However, Walles said that the researchers still need to identify the compounds that the dogs are able to detect in the exhaled breath of patients.

"It is unfortunate that dogs cannot communicate the biochemistry of the scent of cancer," he said.
Lung cancer is the most common cause of death from cancer worldwide.