MALIGNANT TRANSFORMATION OF ORAL LEUKOPLAKIA - A FOLLOW-UP-STUDY OF AHOSPITAL-BASED POPULATION OF 166 PATIENTS WITH ORAL LEUKOPLAKIA FROM THE NETHERLANDS

A follow-up study of a hospital-based population of 166 patients with oral leukoplakia revealed a 2.9% annual malignant transformation rate. The median follow-up period was 29 months. Parameters associated with an increased risk of malignant transformation were female gender (P < 0.025), absence of smoking habits in women (P < 0.05), and a non-homo geneous clinical aspect (P=0.01). For uniform reporting, a recently pr oposed classification and staging system has been used. Leukoplakias i n stage IV, consisting of lesions with moderate or severe epithelial d ysplasia, were associated with an increased risk of malignant transfor mation (P < 0.01). There were no oral subsites associated with an incr eased risk. Patients who had any form of intervention did not have a s tatistically significantly lower chance for malignant transformation t han patients who were kept under surveillance without intervention. (C ) 1998 Elsevier Science Ltd. All rights reserved.