title: Pattern of recurrence of nonsyndromic keratocystic odontogenic tumors.
abstract: OBJECTIVE
  To describe and analyze recurrent pattern of KOTs according to time.
  
  
  METHODS
  This retrospective chart study evaluated histologically confirmed nonsyndromic keratocystic odontogenic tumors (KOT) treated at our institutions between 1975 and 2012.
  
  
  RESULTS
  Mean age at time of diagnosis was 48 years, and male/female ratio was 1.8:1. The typical nonsyndromic KOT lesion was most often found in the posterior mandible, had radiographically smooth borders, and was associated with symptoms and clinical findings, perforated bone, with a thin capsule. Anterior jaw KOT were found more frequently in patients 50 years or older, and maxillary KOTs were more frequently infected. Treatment was enucleation (n = 70) or marsupialization with subsequent enucleation (n = 22). Observation time ranged from 0.5 months to 25 years (mean 53 months). Crude recurrence rate was 29%. Risk of recurrence increased until 7 years after treatment and then remained stable. Patients with impaired general health had a significantly increased risk of recurrence. Tumors in the posterior mandible that had bone perforation and a thin capsule and contained keratin showed increased recurrence rates. Although recurrence rates were similar for both treatment groups, the groups differed in size and tumor site; thus, the results of this study need to be confirmed in a prospective study.
  
  
  CONCLUSIONS
  Time-dependent recurrence pattern of KOTs is described and analyzed. The following follow-up protocol is suggested for patients with impaired health or large lesions: clinical and radiographic examinations at 2, 4, and 7 years, followed by intervals of 3 to 4 years; for other patients: clinical and radiographic examination at 4, 6, and 8 years, followed by intervals of 3 to 4 years.
authors.affiliation: Professor, Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Norway; Senior consultant, Department of Maxillofacial Surgery, Haukeland University Hospital, Bergen, Norway. Electronic address: trond.berge@iko.uib.no.
authors.forename: Trond I
authors.initials: TI
authors.lastname: Berge
authors.affiliation: Resident in Oral and Maxillofacial Surgery, Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Norway; Department of Maxillofacial Surgery, Haukeland University Hospital, Bergen, Norway.
authors.forename: Saedeh B
authors.initials: SB
authors.lastname: Helland
authors.affiliation: Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Norway.
authors.forename: Andreas
authors.initials: A
authors.lastname: Sælen
authors.affiliation: Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Norway.
authors.forename: Maria
authors.initials: M
authors.lastname: Øren
authors.affiliation: Professor, Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway; Senior consultant in Oral Pathology, Haukeland University Hospital, Bergen, Norway.
authors.forename: Anne Christine
authors.initials: AC
authors.lastname: Johannessen
authors.affiliation: Associate professor (Retired), Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Norway.
authors.forename: Liv
authors.initials: L
authors.lastname: Skartveit
authors.affiliation: Oral Surgeon, Department of Oral Surgery, Stavanger University Hospital, Stavanger, Norway.
authors.forename: Bjarte
authors.initials: B
authors.lastname: Grung
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery*; D009807:Odontogenic Cysts / Q000473:pathology* / Q000601:surgery*; D009808:Odontogenic Tumors / Q000473:pathology* / Q000601:surgery*; D012189:Retrospective Studies