Risk co-factors inducing malignant transformation of oral lichen planus: A literature review of clinical studies

Oral lichen planus (OLP) is an autoimmune chronic inflammatory disease. The potential risk of malignant transformation in OLP remains controversial. The aim of the present study was to review original clinical studies published in indexed databases, which assessed the potential risk cofactors which were implicated in the malignant transformation of oral lichen planus. We focused our search to include most of the studies that reported malignant transformation of oral lichen planus using different combinations of the following key indexing terms: oral lichen planus, malignant transformation, smoking, alcohol, chronic inflammation, candida, human papillomavirus (HPV), hepatitis C virus (HCV) and immunosuppression. The animal studies were excluded from our study. Despite a dearth of studies on this topic we have identified consumption of tobacco and/or alcohol, the presence of erosive and/or atrophic areas, infection with candida, HCV, HPV, and immunosuppression as significant cofactors. Patients with OLP with these risk co-factors are at risk of malignant transformation should, therefore be followed up for an extensive period or even for life.