GPs should use their ‘instinct' to identify childhood cancers, say the authors of a large UK study that found NICE alert symptoms have very low predictive value for identifying cancer in primary care.
NICE guidelines on referral for suspected cancer list specific alert symptoms GPs should look out for before referring children and young people; however, researchers say these are ‘meaninglessly all-embracing'.
The researchers used data from the General Practice Research Database, comparing 1,267 children up to 14-years-old diagnosed with cancer, with 15,318 matched controls.
Three months before diagnosis, alert symptoms were recorded in 27% of children who went on to develop cancer, compared with 1% of controls. However, the positive predictive value for cancer of any alert symptom in the three months before diagnosis was only 0.55 per 1,000 children.
NICE currently recommends that if a child presents three or more times with the same problem, with no clear diagnosis, an urgent referral should be made. The researchers showed children diagnosed with cancer did consult more frequently than controls, with 36% consulting four times or more in the three months before diagnosis, compared with only 9% of controls.
But, again, the positive predictive value for cancer in a child who consulted four or more times in these three months was low - 0.13 per 1,000 children.
The authors of the study concluded GPs should rely on ‘additional clues' to assess when a referral is needed, such as consultation frequency, abnormal examination findings, multiple symptoms and their ‘instinct'.
Study co-author Professor Willie Hamilton, professor of primary care diagnostics at Peninsula College of Medicine and Dentistry and a part-time GP, said current guidance was ‘meaninglessly all-embracing' due to the nature of childhood cancer.
‘It's a once in a lifetime diagnosis for GPs so we never pick up sufficient expertise. That said, most of us rapidly get good at spotting "the sick kid" - and that's what we mean by instinct.'
Dr Orest Mulka, a recently retired GP and member of the 2005 NICE guideline development group, said although the NICE guideline was ‘clearly in need of improvement' there would be no simple solution.
‘The guideline is meant to be used in conjunction with previous knowledge of the child and family, parental concern, clinical skills, intuition and the alarm bells that all experienced clinicians grow to recognise,' he said.
Dr Nick Brown, A GP in Chippenham said that childhood cancer is very difficult to pick up, and agrees that it is a case of looking out for the ‘unexplained ill child'.
Cancer alert symptoms in children
SYMPTOM POSITIVE PREDICTIVE VALUE (PER 1,000)
Neurological symptoms 0.83
Source: British Journal of Cancer 2012, published online 12 January