title: Effectiveness of screening colonoscopy in reducing the risk of death from right and left colon cancer: a large community-based study.
abstract: Screening colonoscopy's effectiveness in reducing colorectal cancer mortality risk in community populations is unclear, particularly for right-colon cancers, leading to recommendations against its use for screening in some countries. This study aimed to determine whether, among average-risk people, receipt of screening colonoscopy reduces the risk of dying from both right-colon and left-colon/rectal cancers.
  
  
  
  We conducted a nested case-control study with incidence-density matching in screening-eligible Kaiser Permanente members. Patients who were 55-90 years old on their colorectal cancer death date during 2006-2012 were matched on diagnosis (reference) date to controls on age, sex, health plan enrolment duration and geographical region. We excluded patients at increased colorectal cancer risk, or with prior colorectal cancer diagnosis or colectomy. The association between screening colonoscopy receipt in the 10-year period before the reference date and colorectal cancer death risk was evaluated while accounting for other screening exposures.
  
  
  
  We analysed 1747 patients who died from colorectal cancer and 3460 colorectal cancer-free controls. Compared with no endoscopic screening, receipt of a screening colonoscopy was associated with a 67% reduction in the risk of death from any colorectal cancer (adjusted OR (aOR)=0.33, 95% CI 0.21 to 0.52). By cancer location, screening colonoscopy was associated with a 65% reduction in risk of death for right-colon cancers (aOR=0.35, CI 0.18 to 0.65) and a 75% reduction for left-colon/rectal cancers (aOR=0.25, CI 0.12 to 0.53).
  
  
  
  Screening colonoscopy was associated with a substantial and comparably decreased mortality risk for both right-sided and left-sided cancers within a large community-based population.
authors.affiliation: Department of Family Medicine and Community Health, The Abramson Cancer Center, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Chyke A
authors.identifier: 0000-0001-7495-0285
authors.initials: CA
authors.lastname: Doubeni
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California, USA.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Corley
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, California, USA.
authors.forename: Virginia P
authors.initials: VP
authors.lastname: Quinn
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California, USA.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Jensen
authors.affiliation: Department of Epidemiology & Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York, USA.
authors.forename: Ann G
authors.initials: AG
authors.lastname: Zauber
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, Georgia, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Goodman
authors.affiliation: Department of Family Medicine and Community Health, The Abramson Cancer Center, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Jill R
authors.identifier: 0000-0003-3831-7049
authors.initials: JR
authors.lastname: Johnson
authors.affiliation: Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Shivan J
authors.initials: SJ
authors.lastname: Mehta
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, California, USA.
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Becerra
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California, USA.
authors.forename: Wei K
authors.initials: WK
authors.lastname: Zhao
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, California, USA.
authors.forename: Joanne
authors.initials: J
authors.lastname: Schottinger
authors.affiliation: Division of Cancer Control and Population Sciences, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: V Paul
authors.initials: VP
authors.lastname: Doria-Rose
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California, USA.
authors.forename: Theodore R
authors.initials: TR
authors.lastname: Levin
authors.affiliation: Department of Epidemiology, University of Washington, Seattle, Washington, USA.
authors.forename: Noel S
authors.initials: NS
authors.lastname: Weiss
authors.affiliation: Department of Population Medicine, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Fletcher
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D044682:Colon, Ascending; D044683:Colon, Descending; D012809:Colon, Sigmoid; D044684:Colon, Transverse; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology; D003113:Colonoscopy / Q000706:statistics & numerical data*; D055088:Early Detection of Cancer / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology; D012307:Risk Factors; D012812:Sigmoidoscopy / Q000706:statistics & numerical data
keywords: ADENOCARCINOMA; COLONOSCOPY; COLORECTAL CANCER; SCREENING