Long term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up: the UK Flexible Sigmoidoscopy Screening randomised controlled trail
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Background: This multicentre randomised trial is examining the effect of single flexible sigmoidoscopy (FS) screening on colorectal cancer (CRC) incidence and mortality. Previous analyses of this and other trials have only reported follow-up after FS for a maximum of 12 years. The objective of this analysis was to examine the long-term effects of FS after 17 years of follow-up.
Methods: Between 1994 and 1999, 170,432 eligible men and women, who had indicated on a previous questionnaire that they would probably attend for screening if invited, were randomised to an intervention group (offered FS screening) or a control group (not contacted) in a 1:2 ratio. Randomisation was performed centrally in blocks of 12, and stratified by trial centre, general practice and household type. The primary outcomes were incidence and mortality of CRC. Hazard ratios (HR) and 95% confidence intervals (CI) for CRC incidence and mortality were estimated for intention-to-treat and per-protocol analyses. The trial is registered, number ISRCTN28352761.
Findings: This analysis included 170,034 people (57,098 in the intervention and 112,936 in the control group). During screening and a median of 17.1 years’ follow-up, CRC was diagnosed in 1,230 individuals in the intervention and 3,253 in the control group, and 353 vs. 996 respectively died from CRC. In intention-to-treat analyses, CRC incidence was reduced by 26% (HR 0.74, 95% CI 0.70-0.80) and CRC mortality by 30% (HR 0.70, 95% CI 0.62-0.79). In per-protocol analyses, adjusted for non-compliance, CRC incidence and mortality were 35% (HR 0.65, 95% CI 0.59-0.71) and 41% (HR 0.59, 95% CI 0.49-0.70) lower in attenders.
Interpretation: A single FS continues to provide substantial protection from CRC diagnosis and death, with protection lasting at least 17 years.
Methods: Between 1994 and 1999, 170,432 eligible men and women, who had indicated on a previous questionnaire that they would probably attend for screening if invited, were randomised to an intervention group (offered FS screening) or a control group (not contacted) in a 1:2 ratio. Randomisation was performed centrally in blocks of 12, and stratified by trial centre, general practice and household type. The primary outcomes were incidence and mortality of CRC. Hazard ratios (HR) and 95% confidence intervals (CI) for CRC incidence and mortality were estimated for intention-to-treat and per-protocol analyses. The trial is registered, number ISRCTN28352761.
Findings: This analysis included 170,034 people (57,098 in the intervention and 112,936 in the control group). During screening and a median of 17.1 years’ follow-up, CRC was diagnosed in 1,230 individuals in the intervention and 3,253 in the control group, and 353 vs. 996 respectively died from CRC. In intention-to-treat analyses, CRC incidence was reduced by 26% (HR 0.74, 95% CI 0.70-0.80) and CRC mortality by 30% (HR 0.70, 95% CI 0.62-0.79). In per-protocol analyses, adjusted for non-compliance, CRC incidence and mortality were 35% (HR 0.65, 95% CI 0.59-0.71) and 41% (HR 0.59, 95% CI 0.49-0.70) lower in attenders.
Interpretation: A single FS continues to provide substantial protection from CRC diagnosis and death, with protection lasting at least 17 years.
Date Issued
2017-04-01
Date Acceptance
2017-02-02
Citation
The Lancet, 2017, 389 (10076), pp.1299-1311
ISSN
0140-6736
Publisher
Elsevier
Start Page
1299
End Page
1311
Journal / Book Title
The Lancet
Volume
389
Issue
10076
Copyright Statement
© The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY license.
Sponsor
Department of Health
Cancer Research UK
Medical Research Council (MRC)
Grant Number
09-800-08
16894
G9615910
Subjects
Science & Technology
Life Sciences & Biomedicine
Medicine, General & Internal
General & Internal Medicine
COLORECTAL-CANCER INCIDENCE
COMMITTEE
MORTALITY
RATES
Colorectal Neoplasms
Early Detection of Cancer
Female
Follow-Up Studies
Humans
Incidence
Male
Mass Screening
Middle Aged
Sigmoidoscopy
Time Factors
United Kingdom
Humans
Colorectal Neoplasms
Sigmoidoscopy
Mass Screening
Incidence
Follow-Up Studies
Time Factors
Middle Aged
Female
Male
Early Detection of Cancer
United Kingdom
General & Internal Medicine
11 Medical and Health Sciences
Publication Status
Published
Date Publish Online
2017-02-21