Posted by: Margaret McCartney7 September 2012
I can't be the only GP who has noted an awful lot of coughing. There is a new urgency and a new concern, though; cancer. True, we've always known that a persistant cough can be a sign of serious underlying disease. And certainly, a chronic cough needs medical attention. But is a new NHS awareness campaign – ‘Be clear on cough' - going to do us any favours?
The ‘3 week cough' campaign has a website, which starts off by asking ‘has someone you love had a cough for 3 weeks or more?' (It doesn't say who what to do if they are unlovable.) ‘It might be something more serious' it says, followed by ‘Don't take any excuses. They may need a chest X-ray, even if they've had one before…Help stop their cough and put an end to their worry.' (1) That's curious, because no one seemed to be worried before their ‘loved one' was meant to get them to the doctor with no excuses. Even more curious is the assertion that ‘a chest X-ray is a quick and easy way to find out if everything is OK'.
So what's based in evidence? Do we know, first of all, that awareness campaigns work? When asked, most campaigns will deliver evidence that shortly after the money was spent on advertising, more people had heard of the campaign. But what's really needed is evidence that the campaign led to meaningful improvements in quality and quantity of life – perhaps through better interventions for easier to treat cancer. The evidence provided by the Department of Health for this campaign rests on a pilot scheme which showed that more people had heard of the campaign and that there were ‘extra' attendances for cough eight weeks after the advertising. (2) The number of chest X-rays ordered went up; but did this help detect cancers earlier? Work in Doncaster suggests that more lung cancers can be picked up in areas subjected to awareness campaigns. (3) Before the campaign, the rate of lung cancer detection in the control group had a rate of 108 per 100,000; in the intervention group it was 88 per 100,000. Rates after the campaign were 97 per 100,000 in the control group versus 112 in the control group; and this was not statistically significant (despite the abstract saying ‘There was a 27% increase in lung cancer diagnoses in the intervention area compared with a fall in the control area'). We must also account for lead time bias when trying to assess how useful campaigns like this are; are we diagnosing more cancers earlier but failing to make an impact on mortality? So far, the Doncaster data has showed more lung cancers were being diagnosed at stage III and IV. Not the earlier diagnosis that was hoped for.
How frequently does a cough mean lung cancer? Not often: a 2005 study from Bristol suggested around 65% of presentations of lung cancer involve a cough. (4) However when people are sent questionnaires, around 12% of the population say they have a chronic cough (5), and less than 2% of people seeing their doctors about a chronic cough will be diagnosed with lung cancer. As for chest X-rays, around a quarter of the time, lung cancer will not be detected despite it being present. (6) So with the sizable false negative rate, is this marketing campaign and all the effort attached to it – including prerecorded coughs as part of adverts in bus shelters - really the best we can do to reduce the suffering caused by lung cancer?
I don't think so; and of course money spent on awareness campaigns has to come from somewhere. I'm concerned that only the least ill will pay attention to them. When it comes to awareness campaigns, we need better evidence than this.
Dr Margaret McCartney is a GP in Glasgow
2) Department of Health. Lung Cancer Awareness Campaign cluster briefing slide pack. 2012
3) Athey V, Suckling R, Tod A et al. Early diagnosis of lung cancer: evaluation of a community-based social marketing intervention. Thorax 2012;67:412-7
4) Hamilton W, Peters T, Round A et al. What are the clinical features of lung cancer before the diagnosis is made? A population-based case-control study. Thorax 2005;60:1059-65
5) Ford A, Forman D, Moayyedi P et al. Cough in the community: a cross sectional survey and the relationship to gastrointestinal symptoms. Thorax 2006;61:975-9
6) Stapley S, Sharp D and Hamilton W. Negative chest X-rays in primary care patients with lung cancer. Br J Gen Pract 2006;56:570-3