Published: 17 August 2022
New research funded by NIHR suggests that the backlog of patients waiting for tests as part of the NHS bowel screening programme could be tackled by raising the threshold at which patients are invited for more in depth investigations.
To achieve this, the researchers suggest increasing the blood level on the test that triggers an invitation for a colonoscopy (a scan of the bowel using a small camera), which could reduce the number of people waiting for a colonoscopy without significantly affecting the number of cancers detected.
The NHS bowel screening programme uses a test called FIT (faecal immunochemical testing) to detect blood in samples of poo from people aged 60-75. If the amount of blood detected is above a certain level, the patient is invited for a colonoscopy to look inside their bowel and spot any potential signs of cancer that need treatment or further investigation.
This screening can help detect bowel cancer at an earlier stage when it’s easier to treat, and even prevent it by spotting small growths called polyps that can be removed before they become cancerous. This approach can reduce both the incidence of this cancer and the number of resulting deaths.
As a result of the COVID pandemic, some screening services were paused or less likely to be accessed by patients. This, along with the age at which people are invited for screening being lowered from age 60 to age 50, means the demand for colonoscopy appointments is higher than usual.
Researchers at Queen Mary University of London, funded by the NIHR Policy Research Unit in Cancer Awareness, Screening and Early Diagnosis, investigated two possible solutions to this problem - increasing the time span between screening invitations, or the blood level cutoff that determines which patients are invited for further tests.
Their research, published in the British Journal of Cancer, showed that increasing the threshold for the blood test would result in fewer lives being lost than increasing the time between invitations.
Raising the blood test threshold (from 120 micrograms per gram to 180) could reduce the number of people invited for colonscopies from just over 16,000 to 11,500 for every 100,000 people screened over 15 years. The higher level threshold would mean 1077 cancers would be detected instead of 1142, with 131 cancers prevented instead of 186, and 151 deaths prevented instead of 191.
Lead author and Professor of Cancer Screening at Queen Mary University of London, Stephen Duffy said: “There have been inevitable delays in screens as a result of the pandemic, but the NHS Bowel Cancer Screening Programme is recovering well. There are still pressures due to the age extension. If the programme must be adapted to cope with limited availability of colonoscopy, our results indicate that changing the FIT threshold may be the most useful option.”