Almost 40% of people with an abnormal bowel cancer screening test result ignore their next screening invitation two years later, results from the national screening programme reveal.
By contrast only 13% of people with a normal result failed to continue with screening.
The study – published today in the British Journal of Cancer – was carried out by researchers at University College London, who looked at data for 62,801 people invited for screening under the NHS national bowel cancer screening programme, in which people aged 60-69 in England, 60-74 in Wales and Northern Ireland and 50-74 in Scotland are invited to take a faecal occult blood (FOB) test every two years.
A total of 35,602 people (57%) underwent the initial screen and 34,856 of these were invited again two years later for a repeat screen.
Of 280 people who had an abnormal result in the first round, all of whom were eligible for invitation to the second round of screening, only 61% took part in the repeat screen – compared with 87% of the 34,576 people who initially had a normal result.
Most of the people with an abnormal test result first time had gone through appropriate follow-up specialist investigations and treatments in the interim, but 37 did not -and these people who had not had their abnormal findings investigated were even less likely to take part in the repeat screen. Just 24% of this group underwent another FOB test, compared with 67% of those who complied with follow-up.
Similar results were seen at a third round of screening, and the researchers found both a previous abnormal result and lack of follow up – along with returning the FOB test kit late – were independent risk factors for not responding to a repeat test, after taking into account any other previous screening characteristics or sociodemographics.
The researchers concluded: ‘Late kit return, a definitive abnormal [FOB test] result and failure to comply with follow-up examinations in a previous screening episode were consistently and independently associated with lower repeat uptake.’
The team suggested screening records and other data related to previous screening episodes could be used to identify groups unlikely to respond to repeat screening invitations, in order to target them with ‘tailored communication and assistance’ to try to overcome the barriers.
Lead author Dr Siu Hing Lo said: ‘Our research has identified a small, but high risk group who are failing to continue with bowel cancer screening tests. We urgently need to understand why people are dropping out of bowel cancer screening and not attending the follow-up investigation as we know the test saves lives.’