redOrbit
Thu, 18 Aug 2011 12:12 UTC

New research claims that dogs are able to reliably detect early lung cancer by sniffing samples of patients' breath.

The researchers found that trained animals correctly identified 71 percent of people who had the disease and correctly dismissed 93 percent of those who were healthy.

According to the study, the dogs were able to distinguish between people who had tumors and those who had chronic obstructive pulmonary disease, which is a separate condition also linked to smoking.

Scientists at Schillerhoehe Hospital in Germany say dogs are able to use their sensitive noses to detect chemicals known to volatile organic compounds that are present in cancer sufferers and exhaled in their breath.

Thorsten Walles, the study author, said in a press release: "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. Our results confirm the presence of a stable marker for lung cancer.

"This is a big step forward in the diagnosis of lung cancer, but we still need to precisely identify the compounds observed in the exhaled breath of patients. It is unfortunate that dogs cannot communicate the biochemistry of the scent of cancer!"

Researchers are working on "electronic noses" which would be able to detect the same chemical as the dog. This chemical or combination of smells has not yet been found.

The researchers said: "Unfortunately, dogs cannot communicate the biochemistry of the scent of cancer."

Dr Laura McCallum, science information officer at Cancer Research UK, told BBC News: "Although there are now some intriguing studies suggesting that dogs may be able to smell cancer in some situations, we're still a long way from understanding exactly which 'smelly molecules' they are detecting and if these studies are accurate.

"Because it would be extremely difficult to use dogs in the clinic, further research is being carried out to learn more about these molecules that are released from tumors and whether devices such as 'electronic noses' could help sniff them out."

The researchers published their findings in the European Respiratory Journal.