Treatments of Oral Lichen Planus: a systematical review and meta-analysis study

Oral Lichen Planus (OLP) is a chronic inflammatory condition that affects mucous membranes into the oral ca- vity. OLP may appear as reticular form, the most common, the plaque and erythematous or atrophic forms; rare is the bullous variant. These lesions may cause burning, pain, bleeding or other complaints. The severity and subsequent disability caused by OLP varies from poor to severe. The real cause of OLP is not completely under- stood, but genetics and immunity seem to be involved. Because of this uncertain etiology, treatment strategies are focused on relief of pain and healing of oral lesions. Although many options for treating symptomatic OLP are available, no therapy is curative. The aim of this study is to evaluate the efficacy of different treatment proto- cols through a systematic review and meta-analysis study. The PICO (Patient and problem; Intervention; Comparison; Outcome) model was used to structure the meta- analysis. Randomized clinical trial with crossover tests about different treatment strategies were included in the review of the literature. Selected papers had to be entirely available on the most important medical databases, such as MEDLINE, PUBMED, SCOPUS. Only studies regarding adult patients with clinical and histopathological manifestations were included. The total amount of detected studies for the systematic review was 576. The duplicate studies were removed (286), while 216 were excluded because they did not respect the selected criteria. The remaining 74 studies analysed: different drug therapies (steroids, topic and systemic immunosuppressants, retinoids, biological agents) and non-pharmacological ones (surgery, low level laser therapy and photodinamic therapy). After the identification of all the proposed therapies, a statistical meta-analysis study was realized among 11 of the 74 pa- pers selected, to estimate the efficacy of the most used therapeutic protocols. In particular, clobetasol (topic cor- ticosteroid) and tacrolimus (calcineurin inhibitor) were compared. The considered outcome of the analysis was the clinical improvement of the lesions, in size, frequency of appearance, duration, severity and number. For the statistical analysis, the Cochran’s Q test was used. The results identified a higher efficacy of Tacrolimus (4.29% more than other therapies) compared to Clobetasol (1.21% more than other therapies). These results are compatible with Chamali et al. meta-analysis study (2015). Since many studies reported that Clobetasol may cause oral candidiasis, Tacrolimus could be preferred in either diabetic or immunodeficient patients. However, the most important Tacrolimus contraindication is the risk of cancerization. For this reason, a prolonged use of topic tacrolimus is strongly discouraged. Apparently, calcineurin inhibitors are highly effective in the treatment of lichen planus lesions, but more clinical randomized trials are needed to support a greater diffusion of this proto- col of therapy.