Screening programmes usually focus on our nether parts: the colon and the prostate. We hear little about the lung. Mindful of progress in screening technology, Malcolm Dalrymple-Hay and Nigel Drury of Wessex Cardiothoracic Centre have used the January edition of the Journal of the Royal Society of Medicine to ponder if screening for lung cancer would now make sense.

For the three-quarters of tumours which fall into the category known as 'non-small-cell carcinoma', the case for lung screening has several strengths. These tumours grow more slowly, are relatively late in throwing off secondaries, and respond well to surgery - if detected early enough. Often, of course, they are not. Hence the appeal of screening. What, then, are the prospects?

Simple chest x-rays have proved disappointing.

Examining sputum is cheap, and is non-invasive; unfortunately It is also not very useful. But biotechnology can alter such judgements overnight. It is not too hard to imagine a biotech company developing a test able to detect the products of a tumour before It is large enough to pick up on a scan. So the jury is out on this one.

So the spotlight is likely to fall on the latest generation of CT scanners: rapid, accurate and able to image even small nodules. But snags remain: the higher radiation dose and the equipment costs. The advent of computer-aided diagnosis for interpreting the pictures could alter the score; but not yet.

Dalrymple-Hay and Drury's bitter-sweet conclusion on the likelihood of a UK national screening programme will come as a relief to hardpressed managers: '. . . the resources required are beyond the scope of an overloaded national health service. '