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X-rays failing to find lung cancer

By Danusia Osiowy

GPs are deciding whether to refer for suspected lung cancer on the basis of misleading chest X-ray results, a study warns.

The researchers urged GPs not to rely on X-rays alone to discount lung cancer after finding they missed a quarter of cases.

In the year before diagnosis, 13 per cent of lung cancer patients had an X-ray which was abnormal but did not suggest malignancy and 10 per cent had completely normal results.

Dr William Hamilton, who led the Department of Health-funded study, said: 'Until now we thought false negatives were rare and confined to hospital practice. It's important for GPs not to think that the chest X-ray must be right. If in doubt, repeat the chest X-ray with a lateral or CT scan.'

Dr Hamilton, senior research fellow at the University of Bristol, added: 'Any patient who isn't getting better, or who has multiple symptoms – such as haemoptysis, dyspnoea, cough, or loss of weight – needs further investigation.'

The study, published in August's British Journal of General Practice, examined the records of 164 lung cancer patients who had had a chest X-ray in the year before diagnosis. Few results were positive more than six months before – suggesting there was little use in reviewing earlier X-ray results.

There were false negatives with all common symptoms except hoarseness, which the researchers hypothesised might be a sign of late disease.

The potential of X-rays to mislead was highlighted by a second study which found results changed GP practice in 60 per cent of cases. The Dutch study, also published in the BJGP, found chest X-rays led to fewer referrals, reduction in initiation or change of therapy and more frequent reassurance.

Dr Nick Brown, a GP in Chippenham and cancer lead for Kennet and North Wilts PCT, said: 'Chest X-rays give a false sense of security but access to alternative methods for assessment such as CT scanning is a whole different and difficult ball game.'

Dr Pawan Randev, a GP in Amersham and cancer lead for Ealing PCT, said: 'GPs should have a degree of open access to further investigative methods but unfortunately this is just not in place at the moment.'

Referral without X-ray

• Offer urgent referral while waiting for chest X-ray for:

– persistent haemoptysis in smokers/ex-smokers over 40

– signs of superior vena caval obstruction

– stridor

• If there is a high suspicion of cancer, offer urgent referral even if chest X-ray is normal

• Consider emergency referral for patients with superior vena caval obstruction or stridor

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