Meta-analysis on clinicopathologic risk factors of leukoplakias undergoing malignant transformation

CONTEXT: Leukoplakia is classified under the term potentially malignant disorder. This term does not suggest the clinician or the patient about the severity of the disease to undergo a malignant transformation. Thus, there arises a need to identify the risk factors associated with malignant transformation (MT) to predict it at the earliest. AIMS: To generate evidence regarding the clinicopathologic factors affecting MT in oral leukoplakias. MATERIALS AND METHODS: Meta-analysis was done by extracting data from all the previous studies published. Articles were searched in PubMed databases. STATISTICAL ANALYSIS: Mixed model by using the PROC MIXED (SAS 9.3) was performed to estimate the effect of different factors such as gender, type of habit (smoking tobacco, gutka, paan (with tobacco) and no habit association), clinical type and histopathology on MT. The lower specific mean for MT was also calculated with respect to the above-mentioned factors. RESULTS: Speckled leukoplakias also known as erythroleukoplakia confirmed to be at the highest risk. Lateral border of the tongue followed by gingiva, buccal mucosa, floor of the mouth, lesions involving tongue and floor of mouth showed increased risk. Smoking tobacco (cigarette and bidi) and idiopathic leukoplakia (without habit) carried almost equal risk. Gender had minimal influence on MT. Histopathologic correlation of grades showed an insignificant bearing on MT. CONCLUSION: The carcinogenic transformation of a preexisting lesion (leukoplakia) is multifactorial and patient specific. The protocol to delineate a high-risk lesion should include the clinical type and site.