[Precancerous lesions of the buccal mucosa]

We analyzed data in the literature in comparison with experience at the Department of Cancer and Oral pathology of the Stomatology and Maxillo-Facial Surgery division of la Salpêtrière Hospital on precancerous lesions of the oral mucosa, in order to establish definitions and describe epidemiological, clinical, histological findings as well as natural history and treatment outcome.

Three literature sources were analyzed: Medline and Current Contents searches, books and references listed in articles. The following key words were used and classed into three groups; 1) oral mucosa, epidemiology, precancerous lesions, malignant transformation, dysplasia, leucoplakia, oral lichen planus, erythroplasia, verrucous, cheilitis, candidosis, immunodepression, 2) oral mucosa, tumor markers, carcinogens, keratin, keratinocytes, gene, nuclear proteins, p53 protein, Ki-67 antigen, 3) oral mucosa, therapy, prevention, nutrients. The period chosen ran from 1980 to 1998. This automatic literature search was completed by systematic manual search of summaries in specialized journals published in 1997-1998. The lists of references in the identified articles were consulted and furnished the principal publications concerning precancerous lesions of the buccal mucosa. In all 383 references were selected and analyzed by level of scientific proof. Among these 135 are cited in the text. If data in the literature were insufficient, the physicians at the Department of Cancer and Oral pathology of the Stomatology and Maxillo-Facial Surgery division of La Salpêtrière Hospital were consulted to provide their experience-based recommendations.

Clear and practical definitions drawn from current knowledge were adopted. Precancerous lesions were distinguished from precancerous states. Precancerous lesions included chronic lesions of the oral cavity on which cancer of the oral cavity is known to develop. These were: leucoplakia, oral lichen planus, erythroplasia, papillomatous lesions, actinic cheilitis, submucosal fibrosis, keratotic candidosis, and tertiary syphilis. The precancerous states included cancers occasionally observed in the oral cavity: immunodepression and Plummer Vinson syndrome were analyzed. Epidemiological, clinical, histological, and evolutive data as well as therapeutic strategies were described. A decisional algorithm was elaborated for leucoplakia. The text was enriched with images available in the Department.

Precancerous lesions of the oral mucosa offer a particularly interesting area of research for understanding the process of cancer formation and its prevention. The level of scientific proof available in the large majority of the published reports is low. Few recent publications provide relevant data. In practice, the experience in the management of cancer and precancerous lesions of the oral mucosa accumulated over the last 40 years at the Department of Cancer and Oral pathology of the Stomatology and Maxillo-Facial Surgery division of la Salpêtrière Hospital provides an invaluable source of information.