THE NHS is to investigate whether a screening programme for lung cancer using CT scans should be introduced in the UK.

The Health Technology Assessment (HTA) programme is commissioning a study on the use of a type of sophisticated X-ray - known as low-dose spiral computerised tomography (CT) - to detect tumours in the lungs.

Lung cancer is the biggest cancer killer in the UK, with one person dying from the disease almost every 15 minutes. By the time symptoms become serious enough to visit a doctor, the disease is often extremely difficult to treat successfully.

Medics are interested in CT scans as a screening technique because they can detect smaller tumours than standard X-rays. Studies examining its use for lung cancer are already under way in the US and the Netherlands. Now the HTA, which funds studies for the health service, is commissioning similar research in the UK.

The move has been welcomed by charities, which point out that the disease is far easier to treat if it is diagnosed early. British Lung Foundation spokesman Dr Mick Peake, a consultant physician at Glenfield Hospital, Leicester, said: "This technology offers the real possibility of early diagnosis and the chance to save lives. We have been pushing for this trial for a very long time."

Dr Siow-Ming Lee, a Cancer Research UK lung cancer expert, said the prospect of a screening programme using CT scans was "exciting", but pointed out that evidence it helped to reduce deaths was still lacking.

He also cautioned there are other problems associated with the use of CT scans, such as a high number of "false-positive" results, which can lead to unnecessary invasive investigations and difficulties in managing the anxiety of patients who have benign tumours.

"Studies are currently being conducted in America and Europe examining whether spiral CT scan screening leads to reduced mortality and we should know the results of this trial by 2010," he said.

Mike Unger, chief executive of the Roy Castle Lung Cancer Foundation, said any screening programme was not completely accurate, but it would be a "significant step forward" if it could be used for lung cancer.

Unger also pointed out that a national CT screening programme for lung cancer would only be feasible if it was targeted at those most at risk. The foundation, named after the entertainer who died of cancer contracted through passive smoking, has developed a simple questionnaire, which is being tried out, to help GPs identify patients who may be at increased risk of the disease.

"Every person over the age of 50 is asked five simple questions, such as do you smoke?' and is there a family history of lung cancer?'" Unger said. "From that we can give them a score which will then identify people at high risk: they can then go on to a fast track system of preventing lung cancer, which can include more screening and eventually a CT scan, if that is necessary."

Results from the New York Early Lung Cancer Action Project study this year found an annual CT scan for high-risk patients could help detect tumours when they were most treatable. However, a study in the Journal of the American Medical Association concluded that while CT screening may detect more cancers, there was "no evidence" that it reduced death rates.

Scientists are working on developing alternatives to detect lung cancer, such as blood tests that can detect higher levels of certain proteins in people with the disease. A prototype breath test, which picks up compounds emitted by lung tumours, has been developed by US scientists.