title: Systematic review with meta-analysis: the comparative effectiveness of aspirin vs. screening for colorectal cancer prevention.
abstract: Both aspirin use and screening with flexible sigmoidoscopy or guaiac faecal occult blood testing (FOBT) may reduce mortality from colorectal cancer, but comparative effectiveness of these interventions is unknown.
  
  
  
  To compare aspirin to guaiac FOBT screening with regard to incidence and mortality of colorectal cancer in a network meta-analysis.
  
  
  
  We searched Medline, EMBASE and the COCHRANE central register (CENTRAL) for relevant randomised trials identified until 31 October 2015. Randomised trials in average-risk populations that reported colorectal cancer mortality, colorectal cancer incidence, or both, with a minimum follow-up of 2 years, and more than 100 randomised individuals were included. Three investigators independently extracted data. We calculated relative risks [RR with 95% predictive intervals (PrIs)] for the comparison of the interventions by frequentist network meta-analyses.
  
  
  
  The effect of aspirin on colorectal cancer mortality was similar to FOBT (RR 1.03; 95% PrI 0.76-1.39) and flexible sigmoidoscopy (RR 1.16; 95% PrI 0.84-1.60). Aspirin was more effective than FOBT (RR 0.36; 95% PrI 0.22-0.59) and flexible sigmoidoscopy (RR 0.37; 95% PrI 0.22-0.62) in preventing death from or cancer in the proximal colon. Aspirin was equally effective as screening in reducing colorectal cancer incidence, while flexible sigmoidoscopy was superior to FOBT (RR 0.84; 95% PrI 0.72-0.97).
  
  
  
  Low-dose aspirin seems to be equally effective as flexible sigmoidoscopy or guaiac FOBT screening to reduce colorectal cancer incidence and mortality, and more effective for cancers in the proximal colon. A randomised comparative effectiveness trial of aspirin vs. screening is warranted.
authors.affiliation: Institute of Health and Society, University of Oslo, Oslo, Norway.|Primary Care Research Unit, Vårdcentralen Värmlands Nysäter, Värmland, Sweden.|Department of Transplantation Medicine, K. G. Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway.
authors.forename: L
authors.initials: L
authors.lastname: Emilsson
authors.affiliation: Institute of Health and Society, University of Oslo, Oslo, Norway.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Ø
authors.initials: Ø
authors.lastname: Holme
authors.affiliation: Institute of Health and Society, University of Oslo, Oslo, Norway.|Department of Medicine, Sørlandet Hospital, Kristiansand, Norway.|Department of Transplantation Medicine, K. G. Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Bretthauer
authors.affiliation: Department of Transplantation Medicine, K. G. Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway.|Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: N R
authors.initials: NR
authors.lastname: Cook
authors.affiliation: Department of Transplantation Medicine, K. G. Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway.|Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Buring
authors.affiliation: Institute of Health and Society, University of Oslo, Oslo, Norway.|Department of Medicine, Sørlandet Hospital, Kristiansand, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Løberg
authors.affiliation: Department of Transplantation Medicine, K. G. Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway.|Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: H-O
authors.initials: HO
authors.lastname: Adami
authors.affiliation: Department of Transplantation Medicine, K. G. Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway.|Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: H D
authors.initials: HD
authors.lastname: Sesso
authors.affiliation: Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gaziano
authors.affiliation: Institute of Health and Society, University of Oslo, Oslo, Norway.|Department of Transplantation Medicine, K. G. Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway.|Telemark Hospital, Skien, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Kalager
mesh_terms: D001241:Aspirin / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D055088:Early Detection of Cancer; D006801:Humans; D015994:Incidence; D008403:Mass Screening; D016032:Randomized Controlled Trials as Topic
chemical_list: D001241:Aspirin