Original Research5 June 2018
A Randomized Trial
    Author, Article, and Disclosure Information

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


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


    Randomized controlled trial. (ClinicalTrials.gov: NCT00119912)


    Oslo and Telemark County, Norway.


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


    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.


    Age-adjusted CRC incidence and mortality stratified by sex.


    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).


    Follow-up through national registries.


    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.


    • 1. Bibbins-Domingo KGrossman DCCurry SJDavidson KWEpling JWGarcía FARet alUS Preventive Services Task ForceScreening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA2016;315:2564-75. [PMID: 27304597] doi:10.1001/jama.2016.5989 CrossrefMedlineGoogle Scholar
    • 2. Atkin WWooldrage KParkin DMKralj-Hans IMacRae EShah Uet alLong term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up: the UK Flexible Sigmoidoscopy Screening randomised controlled trial. Lancet2017;389:1299-1311. [PMID: 28236467] doi:10.1016/S0140-6736(17)30396-3 CrossrefMedlineGoogle Scholar
    • 3. Holme ØLøberg MKalager MBretthauer MHernán MAAas Eet alEffect of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: a randomized clinical trial. JAMA2014;312:606-15. [PMID: 25117129] doi:10.1001/jama.2014.8266 CrossrefMedlineGoogle Scholar
    • 4. Schoen REPinsky PFWeissfeld JLYokochi LAChurch TLaiyemo AOet alPLCO Project TeamColorectal-cancer incidence and mortality with screening flexible sigmoidoscopy. N Engl J Med2012;366:2345-57. [PMID: 22612596] doi:10.1056/NEJMoa1114635 CrossrefMedlineGoogle Scholar
    • 5. Segnan NArmaroli PBonelli LRisio MSciallero SZappa Met alSCORE Working GroupOnce-only sigmoidoscopy in colorectal cancer screening: follow-up findings of the Italian Randomized Controlled Trial—SCORE. J Natl Cancer Inst2011;103:1310-22. [PMID: 21852264] doi:10.1093/jnci/djr284 CrossrefMedlineGoogle Scholar
    • 6. Holme ØSchoen RESenore CSegnan NHoff GLøberg Met alEffectiveness of flexible sigmoidoscopy screening in men and women and different age groups: pooled analysis of randomised trials. BMJ2017;356:i6673. [PMID: 28087510] doi:10.1136/bmj.i6673 CrossrefMedlineGoogle Scholar
    • 7. Bretthauer MGondal GLarsen KCarlsen EEide TJGrotmol Tet alDesign, organization and management of a controlled population screening study for detection of colorectal neoplasia: attendance rates in the NORCCAP study (Norwegian Colorectal Cancer Prevention). Scand J Gastroenterol2002;37:568-73. [PMID: 12059059] CrossrefMedlineGoogle Scholar
    • 8. Gondal GGrotmol THofstad BBretthauer MEide TJHoff GThe Norwegian Colorectal Cancer Prevention (NORCCAP) screening study: baseline findings and implementations for clinical work-up in age groups 50-64 years. Scand J Gastroenterol2003;38:635-42. [PMID: 12825872] CrossrefMedlineGoogle Scholar
    • 9. Hoff GSauar JHofstad BVatn MHThe Norwegian guidelines for surveillance after polypectomy: 10-year intervals. Scand J Gastroenterol1996;31:834-6. [PMID: 8888428] CrossrefMedlineGoogle Scholar
    • 10. Atkin WSEdwards RKralj-Hans IWooldrage KHart ARNorthover JMet alUK Flexible Sigmoidoscopy Trial InvestigatorsOnce-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet2010;375:1624-33. [PMID: 20430429] doi:10.1016/S0140-6736(10)60551-X CrossrefMedlineGoogle Scholar
    • 11. Brenner HAltenhofen LKatalinic ALansdorp-Vogelaar IHoffmeister MSojourn time of preclinical colorectal cancer by sex and age: estimates from the German national screening colonoscopy database. Am J Epidemiol2011;174:1140-6. [PMID: 21984657] doi:10.1093/aje/kwr188 CrossrefMedlineGoogle Scholar
    • 12. Kim SEPaik HYYoon HLee JEKim NSung MKSex- and gender-specific disparities in colorectal cancer risk. World J Gastroenterol2015;21:5167-75. [PMID: 25954090] doi:10.3748/wjg.v21.i17.5167 CrossrefMedlineGoogle Scholar
    • 13. Shaukat AMongin SJGeisser MSLederle FABond JHMandel JSet alLong-term mortality after screening for colorectal cancer. N Engl J Med2013;369:1106-14. [PMID: 24047060] doi:10.1056/NEJMoa1300720 CrossrefMedlineGoogle Scholar
    • 14. Schoenfeld PCash BFlood ADobhan REastone JCoyle Wet alCONCeRN Study InvestigatorsColonoscopic screening of average-risk women for colorectal neoplasia. N Engl J Med2005;352:2061-8. [PMID: 15901859] CrossrefMedlineGoogle Scholar
    • 15. Robertson DJKaminski MFBretthauer MEffectiveness, training and quality assurance of colonoscopy screening for colorectal cancer. Gut2015;64:982-90. [PMID: 25804631] doi:10.1136/gutjnl-2014-308076 CrossrefMedlineGoogle Scholar
    • 16. Hewitson PGlasziou PIrwig LTowler BWatson EScreening for colorectal cancer using the faecal occult blood test, Hemoccult. Cochrane Database Syst Rev2007:CD001216. [PMID: 17253456] MedlineGoogle Scholar
    • 17. Swartz AWEberth JMJosey MJStrayer SMReanalysis of all-cause mortality in the U.S. Preventive Services Task Force 2016 evidence report on colorectal cancer screening. Ann Intern Med2017;167:602-3. [PMID: 28828493]. doi:10.7326/M17-0859 LinkGoogle Scholar
    • 18. Robb KALo SHPower EKralj-Hans IEdwards RVance Met alPatient-reported outcomes following flexible sigmoidoscopy screening for colorectal cancer in a demonstration screening programme in the UK. J Med Screen2012;19:171-6. [PMID: 23486697] doi:10.1258/jms.2012.012129 CrossrefMedlineGoogle Scholar
    • 19. Larsen IKGrotmol TBretthauer MGondal GHuppertz-Hauss GHofstad Bet alContinuous evaluation of patient satisfaction in endoscopy centres. Scand J Gastroenterol2002;37:850-5. [PMID: 12190102] CrossrefMedlineGoogle Scholar
    • 20. Senore CEderle AFantin AAndreoni BBisanti LGrazzini Get alAcceptability and side-effects of colonoscopy and sigmoidoscopy in a screening setting. J Med Screen2011;18:128-34. [PMID: 22045821] doi:10.1258/jms.2011.010135 CrossrefMedlineGoogle Scholar