Malignant transformation of oral leukoplakia: a follow-up study

The main objective of the study was to identify the determinants that contribute to the malignant transformation of oral leukoplakia in a group of patients managed in secondary care. A secondary objective was to compare two dysplasia grading systems to determine their utility in assessing the prognosis.

The cohort consisted of 93 patients diagnosed during the period 2009-2013. The variables recorded and analysed included age and sex, clinical presentation (colour) and severity of oral epithelial dysplasia (OED) scored by the WHO (2005) and the binary grading systems. The planned management included excision of high-grade dysplasia and observation of low-grade dysplasia lesions based on the WHO grading system. Patient factors were transcribed from the pathology records and updated using a questionnaire sent out to the whole group of patients. Data were analysed using χ² test and Kaplan-Meier analysis (P < 0.05).

Complete follow-up data were available for 93 patients. Malignant transformation occurred in 7 patients (7.5%) during a mean follow-up period of 30 months. Among the surgically excised group (n = 51), a recurrence of oral leukoplakia was noted in 16 patients (31%). WHO OED grading (P = 0.02) and the presence of red areas (P = 0.012) were useful in predicting malignant transformation with severe epithelial dysplastic lesions and red and white mixed lesions showing higher rates.

Leukoplakias (7.5%) transformed over a mean follow-up period of 30 months. Dysplasia grading and the clinical appearance by colour (mixed white and red) were significant predictors of malignant transformation CLINICAL SIGNIFICANCE: Patients with erythroleukoplakia and those diagnosed with moderate or severe epithelial dysplasia require more intensive interventions as such lesions have a higher risk of developing a malignancy.