Introduction In the English Bowel Cancer Screening Programme (BCSP) subjects returning a weak positive kit (1–4 of the 6 windows positive) are invited to do a 2nd kit and if none of the windows are positive they are invited to complete a 3rd kit. If any windows are then positive subjects are referred for possible investigation; if no windows are positive subjects are discharged from that screening round. This testing algorithm has been criticised for making the screening process too prolonged thereby producing anxiety and drop-outs and the Scottish BCSP has abandoned asking for a 3rd kit on the grounds that the yield was negligible.
Methods We have analysed the outcomes from the 3rd kits returned to the Eastern BCSP Hub from subjects invited for screening between 1 Jan 2011 and 31 March 2012.
Results Over this period over 850,000 subjects aged 60–74 yrs were invited for screening. 4% (20,021) completed 3 kits and of these 16% (3192) had a positive 3rdkit and were referred for further investigation. Of those investigated (2830) 4.4% (125) were found to have bowel cancer compared with 17.8% (298) with cancer found after a single kit and 8.1% (483) with cancer found after completing 2 kits. A further 7% and 12% completing 3 kits were found to have high and intermediate risk adenomas. The mean time from selection for screening to obtaining a definitive result for those completing 3 kits was 63 days compared to 34 days for those completing a single kit (95% of all subjects returning kits) and 49 days for those completing 2 kits (1% of all subjects returning kits).
Conclusion A significant number (14%,125/906) of bowel cancers are detected in those completing 3 kits but this is at the cost of having a screening episode prolonged to almost twice that for subjects obtaining a definitive result after one kit. The intended introduction of faecal immunochemical tests to replace guaiac faecal occult blood tests should allow the use of a simpler and shorter testing algorithm.
Disclosure of Interest None Declared.