[Diagnosis and treatment of oral precancerous lesions]

Risk factors for oral carcinomas have been identified, but there are no reliable markers for assessing the clinical outcome in individual patients with oral precancerous lesions. DNA aneuploidy is now recognized as an early and significant event in carcinogenesis.

We identified 242 patients with oral red or white patches histologically verified as epithelial dysplasias and measured the nuclear DNA content (DNA ploidy) of the lesions to determine whether DNA ploidy could be used to predict the clinical outcome. Disease-free survival was assessed in relation to DNA ploidy and histological grade. The mean duration of follow-up was approximately eight years.

Among 242 patients with verified epithelial dysplasia, a carcinoma developed in 48 (20%). 167 (69%) had diploid lesions, 20 (8%) had tetraploid lesions and 55 (23%) had aneuploid lesions. Of the 167 with diploid lesions, only four (1%) later developed an oral carcinoma. By contrast, 48 of 55 patients with aneuploid lesions (87%) later developed a carcinoma.

The DNA content (DNA ploidy) can be used to predict the risk for oral cancer in a wide range of oral precancerous lesions. By contrast, histological grading of the same lesions does not give any prognostic information. The clinical value of an early identification of oral lesions with malignant cell clones is substantiated by the fact that there are methods for early intervention.