Malignant potential of oral lichen planus: A meta-analysis

Abstract

Purpose: Several studies have pointed out the malignant transformation potential of oral lichen planus, yet the findings are controversial. The aim of this study was to evaluate the malignant transformation rate of oral lichen planus. Methods: An electronic search of the literature was performed in the PubMed MEDLINE database using the descriptors “oral lichen planus” and “malignant transformation” from January 1988 to September 2008. Ninety-five articles were retrieved and assessed for inclusion. Only prospective and retrospective studies that reported the oral lichen planus malignant transformation rates were considered, as well as studies that included the number of cases with clear criteria for diagnosis of the disease. From the 24 selected studies, information on clinical presentation and location of the lesions, and subjects’ gender and age were recorded. Results: From a total of 11,225 cases of oral lichen planus, 183 (1.63%) developed malignant transformation approximately 6 years after the initial diagnosis. The reticular form was the most common clinical presentation, and the jugal mucosa and tongue were the most frequent locations. However, only the clinical presentation of the disease (atypical forms: atrophic, erosive, “in plaque”) and the location of the lesion (tongue) were associated with a higher malignant transformation risk. Conclusion: Epidemiological studies from the last 20 years revealed a malignant transformation rate of 0.27% per year, emphasizing the importance of the clinical follow-up of oral lichen planus patients.