title: New occurrence and recurrence of neoplasms within 5 years of a screening colonoscopy.
abstract: OBJECTIVE
  The fear that colorectal adenomas were missed on initial colonoscopy or that new adenomas have developed is often a rationale for repeating a colonoscopic examination. The aim of this study was to delineate risk factors associated with recurrence of colorectal adenomas after an initial baseline screening colonoscopy.
  
  
  METHODS
  The study population comprised 875 subjects who underwent a baseline screening colonoscopy followed by a second examination 1-5 yr later. Multiple logistic regression was used to assess the influence of potential risk factors on the occurrence or recurrence of colorectal adenomas, the strength of the influence being expressed as an OR with a 95% CI.
  
  
  RESULTS
  Colorectal adenomas were detected in 484 of all patients (55%) at baseline colonoscopy. Within a 1- to 5-yr time interval, 181 patients (37%) had recurrent adenomas (adenomas were removed during the first colonoscopy) and 73 patients (19%) had newly developed adenomas (adenomas were absent on the first colonoscopy). The occurrence of adenomas at baseline screening colonoscopy was the only factor associated with an increased risk for the recurrence of adenomas at follow-up (OR = 2.51, 95% CI = 1.77-3.55). Recurrence was associated with multiple baseline adenomas (4.45, 2.98-6.64) and baseline adenomas larger than 1 cm (2.62, 1.99-3.11). Recurrence was not associated with histology type or family history of colorectal cancer. There was a significant trend for adenomas to recur in the same proximal or distal segment as the baseline adenomas (p = 0.02).
  
  
  CONCLUSIONS
  Colon adenomas tend to recur with greater frequency if the adenomas removed at baseline were either large or multiple. Although patients with large adenomas or multiple adenomas at baseline screening colonoscopy are at a 2.6- to 4.5-fold risk for recurrence of adenomas, the rate of de novo adenoma formation in patients without baseline adenomas may be large enough to warrant repeat colonoscopy at some time in the future. The exact timing of the follow-up colonoscopy needs to be determined.
authors.affiliation: Department of Veterans Affairs Medical Center, Albuquerque, New Mexico 87108, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Avidan
authors.forename: Amnon
authors.initials: A
authors.lastname: Sonnenberg
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Schnell
authors.forename: Jack
authors.initials: J
authors.lastname: Leya
authors.forename: Adrienne
authors.initials: A
authors.lastname: Metz
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Sontag
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D016017:Odds Ratio; D011159:Population Surveillance; D012307:Risk Factors