Evaluation of the clinical and histological effectiveness of isoretinoin in the therapy of oral leukoplakia. Ten years of experience: is management still up-to-date and effective?

Various studies have evaluated the therapeutic effectiveness of vitamin A derivatives in the treatment of oral leukoplakia (OL). Not all the studies have shown concordant results. The aim of our study, which has a 10-year follow-up, was to test the effectiveness of topical therapy based on 0.18% isotretinoin by comparing it with that most frequently used, i.e., at 0.05% concentration. Forty patients with an established diagnosis of OL were involved in the study. The patients were randomly divided into two groups and the drug was administered topically at 0.05% and 0.18% concentrations. The drug was applied twice a day for 3 consecutive months; then it was suspended for 1 month, and the biopsy sample was repeated for the histological follow-up. The higher concentration of the drug, according to the same protocol, was administered to patients who did not benefit from the lower concentration. The results showed a significant reduction in lesions (85%), with no documented topical or systemic adverse reactions at 0.18% concentration. A significant reduction of the aggressiveness of the disease and the disappearance of dysplastic phenomena were observed histologically. The proposed therapeutic protocol was effective toward highly active oral leukoplakia with dysplastic phenomena, and therefore at higher risk of malignant progression.