GPs 'should ignore NICE' on referrals for suspected colorectal cancer
By Nigel Praities
GPs should ignore national guidelines and refer all patients aged 60 and over with rectal bleeding immediately to a specialist for suspected cancer, say researchers.
In the largest study of the area to date in primary care, researchers from the Universities of Bristol and Birmingham quantified the most predictive signs of colorectal cancer and found rectal bleeding held a high enough risk to warrant immediate investigation in older patients.
The research in nearly 5,500 UK patients from the THIN database casts doubt on current NICE referral guidance that recommends only referring patients aged 60 years or older with rectal bleeding if it lasts for six weeks, or is accompanied by diarrhoea.
Rectal bleeding had a positive predictive value ranging from 2.4% to 4.5%. For women the figures were lower but still in the 2% to 3% range.
Dr William Hamilton, lead researcher and senior lecturer in community-based medicine at the University of Bristol, said the research made the argument for current restrictions on referrals for patients with rectal bleeding redundant.
‘GPs gain relatively little experience in the diagnosis of colorectal cancer because the incidence is about one per GP per year, and only a proportion of these are diagnosed in primary care.
‘Our findings strengthen the view that rectal bleeding carries a high enough risk to warrant investigation irrespective of other symptoms.
‘Current guidance requires persistence of bleeding for six weeks, or accompanying diarrhoea. In our opinion, these additional requirements are unnecessary,' he said.
Colorectal cancer survival in the UK is worse than in other European countries and the US as it is often diagnosed later. This new research could improve the speed at which at-risk patients are diagnosed.
Other strongly predictive features included a change in bowel habits, although the researchers said it was difficult to say what this meant in practice.
Dr Hamilton said: ‘We cannot know what features led GPs to write change in bowel habit in the notes in preference to the specific motility symptoms – however, from our results it is clear that they were identifying a riskier feature, and one that warrants investigation.'
A spokesperson from NICE said they would decide whether to review the guideline later this year. 'As part of this process all new information, including this paper, will be considered,' she said.
The paper was published early online in BMC Medicine.Dr William Hamilton Dr William Hamilton