Simple SummaryThe malignant transformation risk of oral lichen planus (OLP) is still a dilemma in the literature. The first report of oral squamous cell carcinoma with the origin of OLP was in 1910. Initially, the reported risk in the literature was high after this date; then, with the application of restricted criteria for the diagnosis of OLP, the reported risk become too low. Currently, there is a recommendation to conduct further studies in which other variables are considered, such as smoking and drinking habits and the type and localization of the lesion. This is in order to evaluate the exact risk of OLP and, correspondingly, to avoid the clinical underestimation by medical staff of the risk of malignant transformation of OLP.AbstractThis study aims to retrospectively assess the potential risk of malignant transformation in patients with diagnosed oral lichen planus (OLP) between 2015 and 2022, and to evaluate the influence of different risk factors. The department’s database and medical records from 2015 to 2022 were searched for patients with a confirmed diagnosis of OLP based on both clinical and histological parameters. A total of 100 patients (59 females and 41 males) were found with a mean age of 64.03 years. In the considered period, the percentage of diagnosed OLP patients was 1.6%, while the percentage of diagnosed OLP patients with transformation to oral squamous cell carcinoma (OSCC) was 0.18%. A statistically significant difference was found with age (p= 0.038), tobacco status (p= 0.022), and radiotherapy (p= 0.041). The analysis revealed the presence of significant risk in ex-smokers (>20 pack-years), with an odds ratio (OR) of 10.0000 (95% confidence interval (95% CI) 1.5793–63.3186); in alcohol-drinker patients, with an OR of 4.0519 (95% CI 1.0182–16.1253); in ex-smoker and alcohol-drinker patients, with OR of 17.6250 (95% CI 2.2464–138.2808); and in patients who had undergone radiotherapy, with OR of 6.3000 (95% CI 1.2661–31.3484). The malignant transformation of oral lichen planus was slightly higher than thought, and the results revealed a possible association with age, tobacco and alcohol status, and history of radiotherapy. An elevated risk of malignant transformation was observed in heavy ex-smoker patients, alcohol-drinker patients, and alcohol-drinker patients with a history of smoking (ex-smokers). Persuading the patient to quit tobacco and alcohol consumption and periodic follow-ups are recommended in general, but particularly in the presence of these risk factors.