An appraisal of highest quality studies reporting malignant transformation of oral lichen planus based on a systematic review.

OBJECTIVES: We present a critical review of the papers published in the international scientific literature on malignant transformation of oral lichen planus (OLP). Our aim is to report the most realistic estimate of the proportion of OLP cases with malignant transformation based on the highest quality of evidence. MATERIALS AND METHODS: Following a literature search, we selected 89 papers that were published on this topic until November 2020. We applied to these papers an adaptation of the methodological quality criteria of the QUIPS tool and we ordered all of them according to their methodological quality. The papers that were in the upper quartile of methodological quality (10 papers) were selected and analyzed. RESULTS: The pooled proportion (expressed as percentage) of malignant transformation of OLP reported in these high methodological quality papers was 2.28% (95% confidence intervals = 1.49-3.20). CONCLUSIONS: We observe that the proportion of malignancy is higher in research carried out under strict methodological quality criteria. In this critical review, we propose criteria for conducting follow-up studies on OLP to report on malignant transformation under strict quality standards.