Sniffer dogs detect lung cancer

Sniffer dogs can detect lung cancer in patients, according to a new study.

Lung cancer is the most common cause of death by cancer in the world and the second most common cancer in Europe, resulting in over 340,000 deaths each year.

But it is not strongly associated with any particular symptoms, making early detection difficult if not impossible - in fact most early detections of the disease are by chance.

Current early detection methods are unreliable, but one area of research has been to look for the presence of volatile organic compounds (VOCs) on patients' breath. VOCs have been linked to the presence of cancer but, as yet, no lung cancer-specific VOCs have yet been identified.

Researchers from Schillerhoehe Hospital in Germany investigated whether trained sniffer dogs could be used to detect VOCs in the breath of lung cancer patients.

In the study, 220 volunteers - 110 healthy people, 60 lung cancer patients and 50 people with chronic obstructive pulmonary disease - breathed into a fleece lined tube, designed to absorb smells.

The dogs then sniffed the tubes, and then had to pick out the person who originally breathed into the tube.

They successfully identified 71 samples with lung cancer out of a possible 100, and correctly detected 372 samples that did not have lung cancer out of a possible 400.

The dogs were also able to detect the lung cancer smells independently from those of COPD and tobacco smoke, suggesting that specific chemicals for lung cancer could be used as a form of early detection.

Dr Thorsten Walles said: "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."

The study is published in the European Respiratory Journal.

This article was published on Thu 18 August 2011