title: Three randomized long-term surveillance trials in patients with sporadic colorectal adenomas.
abstract: OBJECTIVE
  Guidelines for surveillance of patients with previous sporadic colorectal adenomas are based on retrospective long-term follow-up and prospective short-term studies. The aim of the present studies was to compare relative risk (RR) of new neoplasia as well as complications, using different intervals between examinations in long-term surveillance.
  
  
  METHODS
  Between l98l and l991, patients with pedunculated and small, flat and sessile adenomas were allocated at random to a 24 months (group A) or 48 months (group B) interval between surveillance colonoscopies (n=671). Patients with flat and sessile adenomas greater than 5 mm in diameter were randomized to intervals of 6 months (group C) or 12 months (group D) between l981 and 1987 (n=73). Finally, 200 patients with similar adenomas as in groups C and D were randomized to 12 months (group E) or 24 months (group F) from 1988 to 2000. The study ended in 2002.
  
  
  RESULTS
  Advanced adenomas were equally as frequent in group A and group B, but colorectal cancer (CRC) was found significantly more often in group B (RR = 6.2 (1.0-117.4)). Severe complications occurred in 4 patients in group A and 2 patients in group B. Advanced new adenomas tended to be more frequent in group D than in C (p=0.08), but only one CRC was detected and this was in group C. There was no significant difference in the risk of CRC between the E and F groups, but the two cancers in group E were both early stage, in contrast to those in group F. Severe complications were seen in one patient in group E and also in group F.
  
  
  CONCLUSIONS
  The results suggest that 2-year intervals should be used between colonoscopies in patients with previous pedunculated adenomas and small, flat and sessile adenomas, whereas larger, flat and sessile adenomas may need intervals of 1 year.
authors.affiliation: Surgical Department A, Odense Universitetshospital, Odense, Denmark. ole.kronborg@dadlnet.dk
authors.forename: Ole
authors.initials: O
authors.lastname: Kronborg
authors.forename: Ole Dan
authors.initials: OD
authors.lastname: Jørgensen
authors.forename: Claus
authors.initials: C
authors.lastname: Fenger
authors.forename: Morten
authors.initials: M
authors.lastname: Rasmussen
mesh_terms: D000236:Adenoma / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D011159:Population Surveillance; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors