SCREENING: What takes 10,000 women up to 35 years to achieve?

Screening is one of the golden means of medicine. Regular screening can help detect in their earliest stages cancers that might otherwise prove fatal – or so the script reads.

Unfortunately, it’s not that simple. Screening sometimes produces false positives – where a cancer is wrongly detected, thus putting the person through unnecessary stress – while mammograms have spread tumours.

A new study has put into perspective cervical screening. Researchers have found that 10,000 women need to be screened for 35 years – at enormous expense and strain to the medical system – to prevent just one death from cervical cancer. By comparison, a nurse performing just 200 tests each year would have prevented a death from cervical cancer once every 38 years.

For that one prevented death, 152 women will have gone through the unnecessary stress of a false positive, while a further 79 would be referred for further investigation because a benign abnormality had been detected.

Not only is this a waste of valuable medical resource, the screening programme also increases the risks of harm caused by medical intervention, say researchers at the Avon Health Authority.

(Source: British Medical Journal, 2003; 326: 901-4).