NHS Bowel Cancer Screening Programme

NHS Bowel Cancer Screening Programme offers screening every two years to all men and women aged 60 to 74

• people in the invitation age range are automatically sent an invitation, then bowel screening kit, so they can do the test at home
• after the first screening test, you will be sent another invitation and screening kit every two years until you reach 74
• an abnormal result (positive test for haemoglobin in the stool sample) will mean the patient will be offered colonoscopy

Notes (2):

• on 7 June 2016, Public Health Minister Jane Ellison announced that the faecal immunochemical test (FIT) was to replace the guaiac feacal occult blood test (gFOBt) as the test used for bowel screening:
  • FIT:
    • is easier to use and can be measured more reliably by machine than by the human eye
    • is sensitive to a much smaller amount of blood and can detect cancers more reliably and at an earlier stage
    • has increased sensitivity that enables detection of more pre-cancerours lesions
    • needs only a single faecal sample from a single bowel motion compared to 2 samples from 3 different motions for gFOBt
      
      
• Proportion of target population screened (3):
  • an important objective of the BCSP is to maximise uptake in the invited population - i.e. proportion of the eligible population offered screening and have a result documented
  • the expected effectiveness of the bowel screening programme in reducing bowel cancer mortality requires a minimum uptake of 52%
    
    
  • Performance thresholds Acceptable level: >= 52.0% Achievable level: >= 60.0%

Investigating the use of different FIT thresholds and sensitivity for diagnosis of colorectal cancer (4):

• a study investigated the sensitivity for diagnosis of colorectal cancer using FIT at a threshold of 120 μg/g
  • study stated that the current programme threshold used in England of 120 μg/g was estimated to identify 47.8% of CRC and 25.0% of high-risk adenomas (HRA)
  • the lower the FIT threshold the more likely an individual is to have a positive FIT screening result (and the proportion of false positive results increases)
  • in the analysis by Li et al:
    • for FIT values 80-119 μg/g 1 in 7 individuals with a positive FIT would either have a colorectal cancer or a high risk adenoma
    • for FIT values 40-79 μg/g 1 in 10 individuals with a positive FIT would either have a colorectal cancer or a high risk adenoma
    • for FIT values 20-39 μg/g 1 in 25 individuals with a positive FIT would either have a colorectal cancer or a high risk adenoma
    • for FIT values 10-19 μg/g 1 in 171 individuals with a positive FIT would either have a colorectal cancer or a high risk adenoma
    • comparing different FIT levels with different sensitivities for CRC
      • if a FIT at a level of 20 μg/g was used then the sensitivity would be 82.2% for colorectal cancer
      • if a FIT at a level of 40 μg/g was used then the sensitivity would be 71.1% for colorectal cancer
      • if a FIT at a level of 80 μg/g was used then the sensitivity would be 57.8% for colorectal cancer
      • if a FIT at a level of 120 μg/g was used then the sensitivity would be 47.8% for colorectal cancer

Reference:

• 1) http://www.cancerscreening.nhs.uk/bowel/ (accessed December 19th 2012)
• 2) PHE Screening Blog (July 2016) - We're getting ready for bowel screening
• 3) Bowel cancer screening programme standards: valid for data collected from 1 April 2018 (Updated July 26th 2019)
• 4) Li SJ, Sharples LD, Benton SC, Blyuss O, Mathews C, Sasieni P, Duffy SW. Faecal immunochemical testing in bowel cancer screening: Estimating outcomes for different diagnostic policies. J Med Screen. 2021 Sep;28(3):277-285.