Precancerous lesions of the oral cavity: review of the literature and an analysis of cases]

146 patients with precancerous lesions of the oral cavity were observed in our institute between 1988 and 1995. Out of a total of 188 lesions, 110 were single and 36 were multifocal. Histologically 164 lesions were classified as keratosis, 14 as dysplasia, and 10 as lichen ruber planus. 76 patients were treated by cryosurgery, 20 received medical treatment and 3 underwent surgery. Only 47 patients eliminated such risk factors as smoking and alcohol consumption from their daily life-styles. Complete response was 99%, 20.8% and 29.8%, respectively, for cryosurgery, medical treatment and preventive measures. Only 2 patients (1.4%) developed squamous cell carcinoma of the oral cavity. Of these, 1 had had keratosis of the tongue, treated with cryosurgery, while the other had had a medically treated dysplasia of the floor of the mouth. There were 8 precancerous lesion recurrences after cryosurgery and 2 after medical treatment. After cryosurgery 18 new lesions appeared in a site other than the primary site, 4 occurred after medical treatment, 1 after surgery and 2 in patients who had eliminated tobacco and alcohol consumption. Since precancerous lesions constitute a general apparatus disease, a systemic treatment is required which can stimulate cell differentiation and/or suppress the mechanisms inducing carcinogenesis. This may prevent the occurrence of new lesions. For this reason the authors believe that the initial treatment for patients with precancerous lesions should be medical. Loco-regional therapy should be reserved for those cases which do not respond to medical treatment.