A REVOLUTIONARY electronic "nose" can detect lung cancer simply by sniffing people’s breath, scientists claim.
The invention, known as an e-nose, could have major implications for the early diagnosis of the commonest cause of cancer deaths .
The device has been developed at the University of Rome, and, while still in its early stages, has successfully det
ected every lung cancer patient it was used on during a trial.
Like a real nose, the electronic version uses an array of sensors that are not designed to detect any one chemical. Instead they respond to the overall profile of compounds in a sample. Such sensors are already used in the food industry to spot subtle off smells and tastes.
A variety of conditions can lead to specific compounds turning up in the breath. This can include aliphatic acids in the breath of people with liver cirrhosis, and dimethylamine or trimethylamine in the breath of those with failing kidneys.
Lung cancer patients exhale a cocktail of alkanes and benzene derivatives, although the reason for this is unclear.
According to a report in New Scientist magazine, which looked at the efficacy of the "nose", quartz crystal sensors were used which were each coated with a varying substance that binds to a different range of organic chemicals. The crystals’ natural vibration frequency is related to their weight, so this changes as molecules from the sample stick to their coated surface, says the report.
Because of this a complex gas sample such as human breath will create a unique profile of vibrations from a range of crystals.
Scientists tested the e-nose on 60 people at the Forlanini Hospital in Rome, including 35 waiting for an operation to remove a large lung tumour. Each test took just over a minute and the nose successfully pinpointed every cancer patient, according to New Scientist.
Experts are now looking at ways of boosting the nose’s sensitivity to the point where it can detect tumours at an early stage. If successful, this would mean that doctors would no longer have to use an invasive instrument called a bronchoscope to look inside a patient’s lungs and, in some cases, remove a tissue sample.
Carrado Di Natale, the head of the e-nose development team, believes a super-sensitive version of the device might in future be used routinely to screen smokers and other high-risk groups for lung cancer.
"It would be less accurate than bronchoscopy but it would be so much easier," he said.
A total of 1,720 women died from lung cancer in Scotland in 2000 compared to 1,116 deaths from breast cancer.
And while the incidence of lung cancer among men is declining, experts have predicted that it will only start to level off among women between 2010 and 2014.
In Scotland the survival rate at five years for lung cancer is between 6 per cent and 7 per cent compared to 70 per cent for breast cancer.
Smoking and passive smoking causes nine out of ten lung cancers. On average 94 people die every day from lung cancer in the UK.
Richard Sullivan, the head of clinical programmes at Cancer Research UK, said that while smell was important for detecting a disease he was sceptical about the efficiency of the e-nose.
He said: "Smell is very important for detecting disease and this is an interesting twist. But this study is much too small to mean anything."
He added that even a highly sensitive nose could only detect surface tumours, and would never replace the blood tests or scans which alert doctors to the onset of secondary cancers.
Researchers in Cambridgeshire are looking to develop a technique using dogs to detect prostate cancer.
The 12-month project will involve Alsatians and Labradors which will be trained to spot minute signs of cancer in urine samples. It is hoped that the dogs will be able to detect certain proteins that can be found in the blood and urine of prostate cancer patients.
After they are successfully trained, the dogs will be presented with hundreds of urine samples to see how effective the process is.
The idea that dogs can distinguish between cancerous and non-cancerous tissue first surfaced in the United States in 1989, when a woman said that her border collie-doberman cross had spotted a skin tumour on her leg.
The woman claimed that she insisted doctors examine a mole after the dog kept sniffing at the same spot on her leg and the presence of a melanoma was subsequently confirmed.
The full article contains 795 words and appears in The Scotsman newspaper.
