Malignant transformation of oral lichen planus and oral lichenoid lesions: A meta-analysis of 20095 patient data

- Around 1.1% of oral lichen planus (OLP) patients develop oral cancer.
- Smoking, alcoholism, and HCV infection increase OLP malignant potential.
- OLP patients need regular follow up for early cancer detection.

ObjectivesFor over a century, a heated debate existed over the possibility of malignant transformation of oral lichen planus (OLP). We performed this meta-analysis to evaluate the malignant potential of OLP and oral lichenoid lesions (OLL) and investigate the possible risk factors for OLP malignant transformation into oral squamous cell carcinoma (OSCC).Materials and methodsWe searched Medline, Scopus, and Web of Knowledge for relevant observational studies. Data on OLP malignant transformation were calculated as a pooled proportion (PP), using the Der-Simonian Liard method. We performed subgroup analyses by OLP diagnostic criteria, site, and clinical type, using Open Meta[Analyst] software. Data on possible risk factors for malignant transformation were pooled as odds ratios (ORs), using Comprehensive Meta-Analysis software.ResultsPooling data for OLP malignant transformation from 57 studies (19,676 patients) resulted in an overall PP of 1.1% [95% CI: 0.9%, 1.4%], while pooling data from 14 recent studies that used the World Health Organization-2003 diagnostic criteria resulted in an overall-PP of 0.9% [95% CI: 0.5%, 1.3%]. The risk of malignant transformation was higher (PP = 2.5%, 95% CI [1%, 4%]) in OLL patients (419 patients). A significant increase of malignant transformation risk was noted among smokers (OR = 2, 95% CI [1.25, 3.22]), alcoholics (OR = 3.52, 95% CI [1.54, 8.03]), and HCV-infected patients (OR = 5, 95% CI [1.56, 16.07]), compared to patients without these risk factors.ConclusionA small subset of OLP patients (1.1%) develop OSCC; therefore, regular follow-up for these patients is recommended. A higher incidence of malignant transformation was found among smokers, alcoholics, and HCV-infected patients; however, these associations should be further investigated.