title: Occurrence of Distal Colorectal Neoplasia Among Whites and Blacks Following Negative Flexible Sigmoidoscopy: An Analysis of PLCO Trial.
abstract: BACKGROUND
  It is unclear whether the higher rate of colorectal cancer (CRC) among non-Hispanic blacks (blacks) is due to lower rates of CRC screening or greater biologic risk.
  
  
  OBJECTIVE
  We aimed to evaluate whether blacks are more likely than non-Hispanic whites (whites) to develop distal colon neoplasia (adenoma and/or cancer) after negative flexible sigmoidoscopy (FSG).
  
  
  METHODS
  We analyzed data of participants with negative FSGs at baseline in the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial who underwent repeat FSGs 3 or 5 years later. Subjects with polyps or masses were referred to their physicians for diagnostic colonoscopy. We collected and reviewed the records of diagnostic evaluations.
  
  
  METHODS
  Our analytic cohort consisted of 21,550 whites and 975 blacks.
  
  
  METHODS
  We did a comparison by race (whites vs. blacks) in the findings of polyps or masses at repeat FSG, the follow-up of abnormal test results and the detection of colorectal neoplasia at diagnostic colonoscopy.
  
  
  RESULTS
  At the follow-up FSG examination, 304 blacks (31.2 %) and 4183 whites (19.4 %) had abnormal FSG, [adjusted relative risk (RR) = 1.00; 95 % confidence interval (CI), 0.90-1.10]. However, blacks were less likely to undergo diagnostic colonoscopy (76.6 % vs. 83.1 %; RR = 0.90; 95 % CI, 0.84-0.96). Among all included patients, blacks had similar risk of any distal adenoma (RR = 0.86; 95 % CI, 0.65-1.14) and distal advanced adenoma (RR = 1.01; 95 % CI, 0.60-1.68). Similar results were obtained when we restricted our analysis to compliant subjects who underwent diagnostic colonoscopy (RR = 1.01; 95 % CI, 0.80-1.29) for any distal adenoma and (RR = 1.18; 95 % CI, 0.73-1.92) for distal advanced adenoma.
  
  
  CONCLUSIONS
  We did not find any differences between blacks and whites in the risk of distal colorectal adenoma 3-5 years after negative FSG. However, follow-up evaluations were lower among blacks.
authors.affiliation: Department of Medicine, Howard University College of Medicine, Washington, DC, USA. adeyinka.laiyemo@howard.edu.|Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. adeyinka.laiyemo@howard.edu.|Division of Gastroenterology, Department of Medicine, Howard University College of Medicine, 2041 Georgia Avenue, NW, Washington, DC, 20060, USA. adeyinka.laiyemo@howard.edu.
authors.forename: Adeyinka O
authors.initials: AO
authors.lastname: Laiyemo
authors.affiliation: Department of Family Medicine and Community Health at the Perelman School of Medicine, Leonard Davis Institute for Health Economics, and the Center for Public Health Initiatives, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
authors.forename: Chyke
authors.initials: C
authors.lastname: Doubeni
authors.affiliation: Early Detection Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Pinsky
authors.affiliation: Health Services and Economics Branch, Division of Cancer Control and Population Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: V Paul
authors.initials: VP
authors.lastname: Doria-Rose
authors.affiliation: M.D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Bresalier
authors.affiliation: Information Management Services Inc., Rockville, MD, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hickey
authors.affiliation: Information Management Services Inc., Rockville, MD, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Riley
authors.affiliation: Department of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Tim R
authors.initials: TR
authors.lastname: Church
authors.affiliation: Department of Medicine and Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Weissfeld
authors.affiliation: Department of Medicine and Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Schoen
authors.affiliation: Health Services and Economics Branch, Division of Cancer Control and Population Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Pamela M
authors.initials: PM
authors.lastname: Marcus
authors.affiliation: Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Philip C
authors.initials: PC
authors.lastname: Prorok
mesh_terms: D000368:Aged; D044383:Black People / Q000208:ethnology*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000208:ethnology*; D055088:Early Detection of Cancer / Q000379:methods* / Q000639:trends; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms; D010051:Ovarian Neoplasms / Q000175:diagnosis / Q000208:ethnology; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000208:ethnology; D012812:Sigmoidoscopy / Q000379:methods* / Q000639:trends; D044465:White People / Q000208:ethnology*
keywords: PLCO; adenomatous polyps; colorectal cancer disparities; flexible sigmoidoscopy; screening
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