Malignant Transformation in Oral Potentially Malignant Disorders.

Background

In 2020, the World Health Organization (WHO) Collaborating Centre for Oral Cancer convened an international expert workshop to establish an updated consensus on the nomenclature and classification of oral potentially malignant disorders (OPMDs). The working group has defined OPMD as "any oral mucosal abnormality that is associated with a statistically increased risk of developing oral cancer", including leukoplakia, proliferative verrucous leukoplakia, erythroplakia, oral submucous fibrosis, oral lichen planus, actinic keratosis/actinic cheilitis, palatal lesions in reverse smokers, oral lupus erythematosus, dyskeratosis congenita, oral lichenoid lesions, and oral graft-versus-host disease.

Methods

A literature search was conducted to identify the available evidence on the malignant transformation of OPMDs. Systematic reviews with meta-analyses quantifying malignant transformation risks were selected and critically analyzed through narrative synthesis.

Results

Based on the available evidence, the malignant transformation risk is 6.64% (95% CI = 5.21-8.21) for oral leukoplakia, 1.40% (95% CI = 1.07-1.76) for oral lichen planus, 1.38% (95% CI = 0.16-3.38) for oral lichenoid lesions, 43.87% (95% CI = 31.93-56.13) for proliferative verrucous leukoplakia, and 6.00% (95% CI = 2.00-10.00) for oral submucous fibrosis. There is currently insufficient evidence regarding the malignant transformation of the remaining OPMDs.

Conclusions

This narrative review presents the current evidence-based knowledge regarding the malignant transformation risks of the different OPMDs, with the aim of fulfilling the mission of the 3rd Global Oral Cancer Forum.