Survival study of leukoplakia malignant transformation in a region of northern Spain

BACKGROUND: Oral leukoplakia is the most common potentially malignant disorder (PMD) of the oral cavity. The objectives of this study are to determine the clinicopathologic features in a group of patients with oral leukoplakia of Northern Spain (Galicia), determining the factors associated to clinical risk and analyzing the malignant transformation of these patients. MATERIAL AND METHODS: We included 85 patients. We recorded sex and age, habits like alcohol and tobacco, size, clinical appearance, site, number of lesions, and presence or absence of dysplasia. We assess the association between risk factors and transformation and developed a logistic regression analysis. Finally we used the Kaplan-Meier and log-rank test for the survival analysis. RESULTS: 7 patients (8.2%) had malignant transformation. The mean follow-up of the patients was 4.13 years versus 5.58 years of those who developed carcinoma. Only location and initial dysplasia have a statistically significant relationship with malignant transformation, but when applied the long rank test only the presence of dysplasia remains statistically significant(P<0,026). Oral Cancer Free Survival was 81.9% (0.150) at 11 years for the group without dysplasia. CONCLUSIONS: We found that the presence of dysplasia is the only risk factor that is statistically related to the development of a carcinoma. Key words:Leukoplakia, oral cancer and oral precancer, follow-up, malignant transformation.