title: Incident rates of colonic neoplasia according to age and gender: implications for surveillance colonoscopy intervals.
abstract: BACKGROUND
  Current guidelines endorse surveillance colonoscopy at 3 to 5 years following initial detection of neoplasia. However, individual patients' risks may vary according to age and gender. This study aimed to characterize neoplasia recurrence in a large patient cohort undergoing surveillance colonoscopy.
  
  
  METHODS
  All patients undergoing two colonoscopies at least 12 months apart between 1996 and 2000, with detection and removal of a polyp on the index colonoscopy, were identified using our endoscopic database to determine the incidence of colonic neoplasia. Patients were classified according to age (<50, 50-64, 65-74, > or =75 years) and gender.
  
  
  RESULTS
  Overall, 1803 patients underwent two colonoscopies at least 12 months apart (median interval, 140 weeks) with removal of a polyp on initial examination. Polyps > or =5 mm were detected in 334 (19%) patients and polyps > or =10 mm in 105 (6%) on subsequent endoscopy. All age and gender groups were well matched with respect to size of polyp detected on initial colonoscopy (P = 0.2). Kaplan-Meier curves and a Cox proportional hazards model demonstrated similar rates of neoplasia recurrence for all patients irrespective of age and gender.
  
  
  CONCLUSIONS
  Similar rates of neoplasia recurrence were observed among patients of different gender and age groups on surveillance colonoscopy. From a health resource utilization perspective, these findings support current recommendations for similar surveillance intervals for patients regardless of age and gender.
authors.affiliation: Division of Gastroenterology and Hepatology, Gonda 9, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. harewood.gavin@mayo.edu
authors.forename: Gavin C
authors.initials: GC
authors.lastname: Harewood
authors.forename: Garrett O
authors.initials: GO
authors.lastname: Lawlor
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology; D003111:Colonic Polyps / Q000175:diagnosis / Q000453:epidemiology; D003113:Colonoscopy; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011159:Population Surveillance; D011237:Predictive Value of Tests; D017678:Sex Distribution; D012737:Sex Factors