Pattern of recurrence of nonsyndromic keratocystic odontogenic tumors.

Objective: To describe and analyze recurrent pattern of KOTs according to time.

Study Design: 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.