title: The yield of surveillance colonoscopy by adenoma history and time to examination.
abstract: OBJECTIVE
  Surveillance colonoscopy is recommended for subjects with a history of adenomas but there is limited information on the yield of surveillance.
  
  
  METHODS
  A sample of subjects in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial with abnormal flexible sigmoidoscopy and follow-up colonoscopy were queried about subsequent surveillance colonoscopy over a 10-year period. Medical records were obtained to verify procedure dates and histologic findings. Subjects with advanced adenomas, nonadvanced adenoma, nonadenomatous polyps, and no polyps at baseline were included.
  
  
  RESULTS
  At the first surveillance, 10.5% had advanced adenoma and 37% had any adenoma in the advanced adenoma group (n = 1057), compared with rates of 6.8% and 32% (nonadvanced adenoma: n = 765), 4.9% and 22% (nonadenomatous polyps: n = 658), and 3.1% and 16% (no polyps: n = 127) (P < .0001, linear trend test). Mean (SD) time intervals (years) from baseline colonoscopy to first surveillance were 3.4 (2.0) for advanced adenoma, 4.3 (2.0) for nonadvanced adenoma, 4.5 (2.0) for nonadenomatous polyps, and 4.7 (2.0) for no polyps. There were no increasing (or decreasing) trends in the observed rate of advanced adenoma or any adenoma with time to the initial surveillance examination in any baseline group. Among subjects with a second surveillance examination, adenoma findings at both baseline and first surveillance influenced the rates of advanced adenoma and any adenoma at second surveillance.
  
  
  CONCLUSIONS
  Subjects with baseline advanced adenomas are more likely to have recurrent advanced adenomas at initial surveillance. The lack of association between recurrence rates and time to surveillance suggests limitations in our understanding of the biology of adenoma development.
authors.affiliation: Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland, USA. pp4f@nih.gov
authors.forename: Paul F
authors.initials: PF
authors.lastname: Pinsky
authors.forename: Robert E
authors.initials: RE
authors.lastname: Schoen
authors.forename: Joel L
authors.initials: JL
authors.lastname: Weissfeld
authors.forename: Timothy
authors.initials: T
authors.lastname: Church
authors.forename: Lance A
authors.initials: LA
authors.lastname: Yokochi
authors.forename: V Paul
authors.initials: VP
authors.lastname: Doria-Rose
authors.forename: Philip
authors.initials: P
authors.lastname: Prorok
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology*; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology*; D003113:Colonoscopy; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D013997:Time Factors