Malignant Transformation of Oral Lichen Planus—An Umbrella Study of Systematic Reviews

Abstract

Oral lichen planus (OLP) is classified as a potentially malignant disorder. Systematic reviews collating longitudinal observation studies provide evidence of the rate or proportion of malignant transformation. We conducted an umbrella study of published systematic reviews. An extensive English-language study search was carried out in several databases to identify relevant articles, providing systematic reviews on the malignant transformation of OLP. Data from eight systematic reviews published between 2014 and 2023 are presented. The reported proportions of malignant transformation ranged from 1.1% to 1.4%. A meta-analysis based on the 10 highest-quality studies yielded a higher proportion of malignant transformation (2.28%). We list some limitations found in several of these systematic reviews. Some studies reported an increased risk of malignancy in OLP lesions, demonstrating epithelial dysplasia. In view of the consistent evidence of the risk of oral malignancy, OLP patients should be monitored carefully to detect early cancer development.