Long-Term Effectiveness of Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality in Women and Men: A Randomized Trial

Øyvind Holme; Magnus Løberg; Mette Kalager; Michael Bretthauer; Miguel A Hernán; Eline Aas; Tor J Eide; Eva Skovlund; Jon Lekven; Jörn Schneede; Kjell Magne Tveit; Morten Vatn; Giske Ursin; Geir Hoff; NORCCAP Study Group†

doi:10.7326/M17-1441

Long-Term Effectiveness of Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality in Women and Men: A Randomized Trial

Ann Intern Med. 2018 Jun 5;168(11):775-782. doi: 10.7326/M17-1441. Epub 2018 Apr 24.

Authors

Collaborators

Affiliations

¹ Sørlandet Hospital Kristiansand, Kristiansand, Norway, and University of Oslo Institute of Health and Society and Oslo University Hospital, Oslo, Norway (Ø.H., M.L., M.B., T.J.E.).
² University of Oslo Institute of Health and Society and Oslo University Hospital, Oslo, Norway, and Harvard T.H. Chan School of Public Health and Harvard-MIT Division of Health Sciences and Technology, Boston, Massachusetts (M.K., M.A.H.).
³ Harvard T.H. Chan School of Public Health and Harvard-MIT Division of Health Sciences and Technology, Boston, Massachusetts; University of Oslo Institute of Health and Society, Oslo, Norway (E.A.).
⁴ Oslo University Hospital, Oslo, Norway; orwegian University of Science and Technology, Trondheim, Norway (E.S.).
⁵ University of Bergen Surgical Research Laboratory, Bergen, Norway (J.L.).
⁶ Umeå University Clinical Pharmacology Unit, Umeå, Sweden (J.S.).
⁷ Oslo University Hospital and University of Oslo Institute of Clinical Medicine, Oslo, Norway (K.M.T., M.V.).
⁸ University of Oslo Institute of Clinical Medicine, Oslo, Norway; Cancer Registry of Norway and University of Oslo Institute of Basic Medical Sciences, Oslo, Norway, and University of Southern California Keck School of Medicine, Los Angeles, California (G.U.).
⁹ University of Oslo Institute of Clinical Medicine and Cancer Registry of Norway, Oslo, Norway, and Telemark Hospital, Skien, Norway (G.H.).

Abstract

Background: The long-term effects of sigmoidoscopy screening on colorectal cancer (CRC) incidence and mortality in women and men are unclear.

Objective: To determine the effectiveness of flexible sigmoidoscopy screening after 15 years of follow-up in women and men.

Design: Randomized controlled trial. (ClinicalTrials.gov: NCT00119912).

Setting: Oslo and Telemark County, Norway.

Participants: Adults aged 50 to 64 years at baseline without prior CRC.

Intervention: Screening (between 1999 and 2001) with flexible sigmoidoscopy with and without additional fecal blood testing versus no screening. Participants with positive screening results were offered colonoscopy.

Measurements: Age-adjusted CRC incidence and mortality stratified by sex.

Results: Of 98 678 persons, 20 552 were randomly assigned to screening and 78 126 to no screening. Adherence rates were 64.7% in women and 61.4% in men. Median follow-up was 14.8 years. The absolute risks for CRC in women were 1.86% in the screening group and 2.05% in the control group (risk difference, -0.19 percentage point [95% CI, -0.49 to 0.11 percentage point]; HR, 0.92 [CI, 0.79 to 1.07]). In men, the corresponding risks were 1.72% and 2.50%, respectively (risk difference, -0.78 percentage point [CI, -1.08 to -0.48 percentage points]; hazard ratio [HR], 0.66 [CI, 0.57 to 0.78]) (P for heterogeneity = 0.004). The absolute risks for death from CRC in women were 0.60% in the screening group and 0.59% in the control group (risk difference, 0.01 percentage point [CI, -0.16 to 0.18 percentage point]; HR, 1.01 [CI, 0.77 to 1.33]). The corresponding risks for death from CRC in men were 0.49% and 0.81%, respectively (risk difference, -0.33 percentage point [CI, -0.49 to -0.16 percentage point]; HR, 0.63 [CI, 0.47 to 0.83]) (P for heterogeneity = 0.014).

Limitation: Follow-up through national registries.

Conclusion: Offering sigmoidoscopy screening in Norway reduced CRC incidence and mortality in men but had little or no effect in women.

Primary funding source: Norwegian government and Norwegian Cancer Society.

Publication types

Randomized Controlled Trial
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Cause of Death
Colorectal Neoplasms / diagnosis
Colorectal Neoplasms / epidemiology*
Colorectal Neoplasms / mortality*
Early Detection of Cancer / methods*
Female
Follow-Up Studies
Humans
Incidence
Male
Mass Screening / methods*
Norway / epidemiology
Occult Blood
Proportional Hazards Models
Registries
Risk Reduction Behavior
Sex Factors
Sigmoidoscopy*

Associated data

ClinicalTrials.gov/NCT00119912

Grants and funding

P01 CA134294/CA/NCI NIH HHS/United States