Screening drop-out rate higher after abnormal FOB test

Screening drop-out rate higher after abnormal FOB test

The study showed that the proportion who dropped out of screening was far lower among people who had had a normal result.

Researchers from the Health Behaviour Research Centre at University College London analysed anonymised data from the Southern Hub of England’s bowel cancer screening programme (BCSP), covering 62,081 people aged 60-74 who had been invited to have a guaiac faecal occult blood test (gFOBt). They looked at which factors were associated with participation at a second (R2) or third (R3) invitation for screening.

They found that, overall, repeat uptake was 86.6% in R2 and 88.6% in R3. However, nearly 40% of people who had had abnormal results from bowel cancer screening tests and were referred for further investigation such as a colonoscopy, to rule out cancer, ignored their next screening invitation two years later – compared with only 13% of those who had had a normal result failed to continue with screening.

Failure to continue screening was associated with a definitive abnormal gFOBt result in the previous screening episode; in this group, non-compliance with follow-up in a previous screening episode was also associated with lower repeat uptake. Weak positive and spoilt test kits were associated with lower repeat uptake, but were not consistently independent predictors in all invitation rounds or subgroups.

The researchers said: “Previous screening episode factors related to both the gFOBt and follow-up are predictive of subsequent gFOBt uptake, independent of sociodemographic and other previous screening episode factors. This is remarkable in the light of high overall uptake of repeat screening invitations. Socioeconomic deprivation was the only sociodemographic factor consistently associated with repeat uptake, independent of previous screening episode factors.”

The same research team had previously reported** that 11-12% of people referred for further investigations such as colonoscopy or an alternative test do not attend the appointments for this.

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 investigations as we know the test saves lives."

Julie Sharp, head of health information at Cancer Research UK, which supported the study, added: "It's a concern to see that people who have abnormal results are dropping out of the screening programme. It's really important to repeat the test every two years and Cancer Research UK is working hard to make people aware of bowel screening and help to remove any barriers that might be stopping them from taking the test."

* Lo et al. Predictors of repeat participation in the NHS bowel cancer screening programme. British Journal of Cancer (2015) 112, 199–206. doi:10.1038/bjc.2014.569

** Lo et al. Colorectal cancer screening uptake over three biennial invitation rounds in the English bowel cancer screening programme. Gut, May 2014. doi:10.1136/gutjnl-2013-306144

By Louise Prime,

OnMedica, Thursday 8 Jannuary 2015

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