Malignant transformation of oral leukoplakia with a focus on low-grade dysplasia

ObjectiveOral leukoplakia (OL) is classified as a precancerous lesion with potential for malignant transformation. No consensus has been reached regarding appropriate treatment for OL with low-grade dysplasia (LGD). We have often seen that OL with LGD that goes untreated or is excised with insufficient margins develops into squamous cell carcinoma. The aim of this study was to identify the rate of and clarify risk factors for malignant transformation of OL, with a focus on LGD.MethodsConsecutive patients with OL with LGD treated between 2000 and 2011 were selected from the medical records of the Department of Oral and Maxillofacial Surgery at Tokyo Dental College, Chiba Hospital, Japan. Differences between clinical characteristics (age, sex, lesion site, smoking habit, alcohol intake, clinical appearance, lesion color, lesion surface, degree of dysplasia and treatment) and malignant transformation were analyzed using Fisher's exact test.ResultsA total of 115 OL patients with LGD were evaluated. Four cases (3.5%) showed malignant transformation to squamous cell carcinoma. No clinical characteristics showed any significant correlation with malignant transformation.ConclusionsStrict follow-up is recommended for OL with LGD to detect oral cancer in the early stage. Biomarkers to identify malignant transformation of leukoplakia are needed to facilitate treatment of these patients and confirm the malignant transformation rate.