• potentially malignant oral disorder;
  • oral leukoplakia;
  • malignant transformation;
  • oral epithelial dysplasia;
  • oral cancer


Oral leukoplakia is a potentially malignant disorder of the oral mucosa. The aim of this retrospective study was to identify the factors that possibly predict malignant transformation in a well-defined cohort of patients with a long-term follow-up. All leukoplakias were staged according to a clinicopathological classification and staging system. Furthermore, a certainty factor has been used with which the diagnosis has been established.

Material and methods

The group consisted of 144 patients. The size, presence and degree of epithelial dysplasia were incorporated into a clinicopathological classification and staging system. Initial management consisted of surgical excision, CO2 laser vaporisation or observation only. The mean follow-up period was 51.2 months (s.d. = 39.33, range 12–179 months).


In 16 of 144 patients (11%), malignant transformation occurred between 20 and 94 months (mean 57.0 months) after the first visit, the annual malignant transformation rate being approximately 2.6%. A large size of the lesion (≥ 4 cm) showed to be the only statistically significant predictor of malignant transformation (P = 0.034).


A size of ≥ 4 cm showed to be the only significant predicting factor of malignant transformation in oral leukoplakia. No other epidemiological, aetiological, clinical or histopathological parameters were of statistical significance.