K.P. Schepman

Malignant transformation of oral leukoplakia: a follow-up study of a hospital-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-homogeneous clinical aspect (P = 0.01). For uniform reporting, a recently proposed classification and staging system has been used. Leukoplakias in stage IV, consisting of lesions with moderate or severe epithelial dysplasia, were associated with an increased risk of malignant transformation (P < 0.01). There were no oral subsites associated with an increased risk. Patients who had any form of intervention did not have a statistically significantly lower chance for malignant transformation than patients who were kept under surveillance without intervention.

Oral leukoplakia: a clinicopathological review

Leukoplakia is the most common premalignant or potentially malignant lesion of the oral mucosa. It seems preferable to use the term leukoplakia as a clinical term only. When a biopsy is taken, the term leukoplakia should be replaced by the diagnosis obtained histologically. The annual percentage of malignant transformation varies in different parts of the world, probably as a result of differences in tobacco and dietary habits. Although epithelial dysplasia is an important predictive factor of malignant transformation, it should be realized that not all dysplastic lesions will become malignant. On the other hand non-dysplastic lesions may become malignant as well. In some parts of the world the tongue and the floor of the mouth can be considered to be high-risk sites with regard to malignant transformation of leukoplakia, while this does not have to be the case in other parts of the world. The cessation of tobacco habits, being the most common known aetiological factor of oral leukoplakia, has been shown to be an effective measure with regard to the incidence of leukoplakia and, thereby, the incidence of oral cancer as well. Screening for oral precancer may be indicated in individuals at risk.

A review of the recent literature regarding malignant transformation of oral lichen planus

On the basis of a literature review of the period 1950-1976, Krutchkoff et al questioned the possible premalignant nature of oral lichen planus. Their criticism was largely based on insufficiencies of data in support of the initial diagnoses of the condition. In this article, a review of the literature from the period 1977-1999 has been described; the criteria used were those of Krutchkoff et al. Thirty-three (34%) of 98 reported cases were accepted as having sufficiently documented evidence of malignant transformation of oral lichen planus. Although this percentage is somewhat higher than the percentage reported by Krutchkoff et al, there apparently remains a need for uniformly accepted criteria to establish a firm diagnosis of oral lichen planus. Only when such criteria are available will it be possible to conduct long-term prospective studies on the suggested possible premalignant nature of oral lichen planus.

A modified classification and staging system for oral leukoplakia

A proposal for a modified classification and staging system for oral leukoplakia (OLEP) has been presented in which the size of the leukoplakia and the presence or absence of epithelial dysplasia are taken into account. Altogether four stages are recognised. The presently proposed system should facilitate uniform reporting of treatment or management results of OLEPs in which a biopsy has become available. The system can easily be adjusted by replacing the histopathological criteria of epithelial dysplasia by a clinical subdivision in homogeneous and non-homogeneous leukoplakia for cases in which no biopsy is available.

Prevalence study of oral white lesions with special reference to a new definition of oral leucoplakia

In this survey, the experiences with and implications of a revised definition of oral leucoplakia are described. One of the new aspects of the revised definition is the distinction between a provisional, clinical diagnosis and a definitive one for which histopathological examination is required. A prevalence study of white lesions of the oral mucosa among a selected population of 1000 consecutive patients from the Netherlands showed a prevalence of a provisional and definitive diagnosis of oral leucoplakia of 0.6 and 0.2%, respectively. For uniform reporting, a recently proposed classification and staging system has been used to stage leucoplakias with a definitive diagnosis. The use of the revised definition of oral leucoplakia, as well as the classification and staging system, seem very suitable for epidemiological studies.

A proposal for a classification and staging system for oral leukoplakia: a preliminary study

A classification and staging system for oral leukoplakia is proposed based on the recently revised definition of this premalignant lesion. The initial experiences of this system are described on the basis of 100 patients with oral leukoplakia. The new classification and staging system seems very suitable for characterizing groups of patients with oral leukoplakia. Whether this system is also valuable with regard to guidelines for management of these patients has still to be proven.