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Bending the Curve Trial by Trial
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UK Flexible Sigmoidoscopy Screening Trial: once-only flexible sigmoidoscopy screening in prevention of colorectal cancer

N = 170,432

Population
Men and women aged 55 to 64 years who had indicated willingness to be screened on a previous questionnaire.
Design
Multicentre randomised controlled trial in 14 UK centres; 170,432 eligible men and women who had indicated on a previous questionnaire that they would accept (or probably attend) an invitation to screening were randomly allocated 1:2 to an offer of once-only flexible sigmoidoscopy between ages 55 and 64 or to a control group that was not contacted. Analyses were intention to treat and per protocol (adjusted for self-selection or non-compliance).
Primary endpoint
Colorectal cancer incidence, Colorectal cancer mortality
Arms
  • Offered flexible sigmoidoscopy (experimental, n = 57,237): Once-only flexible sigmoidoscopy screening
  • Control (not contacted) (control, n = 113,195): No contact, no screening offered
People
Atkin WS
Colorectal cancer mortalityHR 0.69 (95% CI 0.59–0.82)Colorectal cancer incidenceHR 0.77 (95% CI 0.70–0.84)Colorectal cancer mortalityHR 0.57 (95% CI 0.45–0.72)Colorectal cancer incidenceHR 0.67 (95% CI 0.60–0.76)Colorectal cancer mortalityHR 0.70 (95% CI 0.62–0.79)Colorectal cancer incidenceHR 0.74 (95% CI 0.7–0.8)
Show the numbers
Results reported for UK Flexible Sigmoidoscopy Screening Trial: once-only flexible sigmoidoscopy screening in prevention of colorectal cancer
EndpointAnalysisOffered flexible sigmoidoscopyControl (not contacted)Effect
Colorectal cancer mortalityIntention-to-treat analysisprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.69 (95% CI 0.59–0.82)
Colorectal cancer incidenceIntention-to-treat analysisprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.77 (95% CI 0.70–0.84)
Colorectal cancer mortalityPer-protocol analysis, people attending screening, adjusted for self-selection biasprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.57 (95% CI 0.45–0.72)
Colorectal cancer incidencePer-protocol analysis, people attending screening, adjusted for self-selection biasprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.67 (95% CI 0.60–0.76)
Colorectal cancer mortalityIntention-to-treat analysislong term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.70 (95% CI 0.62–0.79)P<0.0001
Colorectal cancer incidenceIntention-to-treat analysislong term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.74 (95% CI 0.7–0.8)P<0.0001
Colorectal cancer mortalityPer-protocol analysis, adjusted for non-compliance (screened group)long term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.59 (95% CI 0.49–0.70)
Colorectal cancer incidencePer-protocol analysis, adjusted for non-compliance (screened group)long term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.65 (95% CI 0.59–0.71)
Results reported for UK Flexible Sigmoidoscopy Screening Trial: once-only flexible sigmoidoscopy screening in prevention of colorectal cancer
EndpointAnalysisOffered flexible sigmoidoscopyControl (not contacted)Effect
Colorectal cancer mortalityIntention-to-treat analysisprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.69 (95% CI 0.59–0.82)
Colorectal cancer incidenceIntention-to-treat analysisprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.77 (95% CI 0.70–0.84)
Colorectal cancer mortalityPer-protocol analysis, people attending screening, adjusted for self-selection biasprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.57 (95% CI 0.45–0.72)
Colorectal cancer incidencePer-protocol analysis, people attending screening, adjusted for self-selection biasprimarymedian follow-up 11.2 yearsAtkin 2010——HR 0.67 (95% CI 0.60–0.76)
Colorectal cancer mortalityIntention-to-treat analysislong term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.70 (95% CI 0.62–0.79)P<0.0001
Colorectal cancer incidenceIntention-to-treat analysislong term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.74 (95% CI 0.7–0.8)P<0.0001
Colorectal cancer mortalityPer-protocol analysis, adjusted for non-compliance (screened group)long term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.59 (95% CI 0.49–0.70)
Colorectal cancer incidencePer-protocol analysis, adjusted for non-compliance (screened group)long term-updatemedian follow-up 17.1 yearsAtkin 2017——HR 0.65 (95% CI 0.59–0.71)
Hazard ratio (95% CI) by endpoint. Values below 1 favour the experimental arm.
Colorectal cancer mortalityColorectal cancer incidenceColorectal cancer mortalityColorectal cancer incidenceColorectal cancer mortalityColorectal cancer incidenceColorectal cancer mortalityColorectal cancer incidence0.512◀ experimentalcontrol ▶
Data table
EndpointHR95% CI
Colorectal cancer mortality0.690.59–0.82
Colorectal cancer incidence0.770.7–0.84
Colorectal cancer mortality0.570.45–0.72
Colorectal cancer incidence0.670.6–0.76
Colorectal cancer mortality0.70.62–0.79
Colorectal cancer incidence0.740.7–0.8
Colorectal cancer mortality0.590.49–0.7
Colorectal cancer incidence0.650.59–0.71
Primary publication: Atkin WS, Edwards R, Kralj-Hans I, Wooldrage K, Hart AR, Northover JM, et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet. 2010;375(9726):1624-33. PubMedDOI

Appears in

Sources

  1. Atkin WS, Edwards R, Kralj-Hans I, Wooldrage K, Hart AR, Northover JM, et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet. 2010;375(9726):1624-33.

    PubMedDOI

  2. Atkin W, Wooldrage K, Parkin DM, Kralj-Hans I, MacRae E, Shah U, et al. Long term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up: the UK Flexible Sigmoidoscopy Screening randomised controlled trial. Lancet. 2017;389(10076):1299-1311.

    PubMedDOI