Prognostic factors for keratocystic odontogenic tumor (odontogenic keratocyst): analysis of clinico-pathologic and immunohistochemical findings in cysts treated by enucleation.

BACKGROUND: The purpose of this study was to determine prognostic factors for the recurrence of keratocystic odontogenic tumors (KCOTs) following simple enucleation by examining clinico-pathologic and immunohistochemical findings.
METHODS: Following enucleation, the frequency of recurrence among 32 subjects diagnosed with KCOT was analyzed for tumor site, radiographic and histologic features, and immunopositivity for Ki-67 and p53.
RESULTS: Keratocystic odontogenic tumors in four out of 32 subjects (12.5%) recurred during the follow-up period (median: 33 months, range: 7-114 months). Three out of four subjects (75.0%) among recurrent group showed high expression of Ki-67 (LI >10%) in basal layer and four (4/28; 14.3%) among non-recurrence group (P = 0.025). Expression of p53 among non-recurrent group was observed in 11 subjects (11/28; 39.3%), and in three subjects (3/4; 75.0%) among the recurrent group (P = 0.295). Hazard risk for the recurrence of KCOT was 4.02 (95% CI 1.42-18.14) for high Ki-67 expression in the basal layer by the Cox proportional hazard model (P = 0.009). In our study, none of the other clinico-pathologic variables were associated with the recurrence of KCOT.
CONCLUSION: The results suggested that the evaluation of Ki-67 expression in KCOT at the time of pathological diagnosis might be helpful for consideration of appropriate adjunctive surgical procedures to avoid a recurrence and may serve as a prognostic marker.