Colorectal cancer screening detects 40% of cases
Screening for colorectal cancer can detect around four out of every 10 cancers, a major analysis reveals.
The research has prompted warnings that the UK's screening programme should not distract from the importance of spotting early symptoms, which is set to remain the most important route of diagnosis.
The UK is one of more than 50 countries to have introduced a screening programme to detect colorectal cancer. The UK programme involves biennial faecal occult blood tests of all men and women aged 60 to 69, and will achieve nationwide coverage by 2009.
Researchers from the Finnish Cancer Registry examined whether Finland's similar national colorectal cancer screening programme successfully detected the disease.
The programme, covering 106,000 people aged 60 to 64 randomised to either a screening or a control group, found faecal occult blood testing was able to detect 55% of cancers in the detectable preclinical phase, and more than a third (38%) in the total target population.
The researchers also found the sensitivity of the test was 55% when considering cancers that developed after positive tests. The sensitivity of the screening episode was 51%, which fell to 38% for the sensitivity of the screening programme as a whole.
Dr William Hamilton, a GP in Exeter with a research interest in colorectal cancer screening, said: ‘The results are striking in their similarity to the UK programme. The big advantage of this Finnish study is its control group, allowing the programme sensitivity – the key measure – to be determined.
‘Perhaps my main concern is that these well conducted trials of good programmes give the wrong overall impression. Screening works. But with the programme sensitivity being 37%, the majority of cancers will still present with symptoms. So symptomatic diagnosis is – and will remain – by far the most important method for years to come.'