The impact of laryngeal dysplasia on the development of laryngeal squamous cell carcinoma.

The aims of this study were to investigate the clinical course of patients with laryngeal dysplasia of various grades after surgical removal and analyze the percentage and time frame in which laryngeal dysplasia progresses to invasive carcinoma. The files of patients with surgical removal of laryngeal dysplasia and at least two microlaryngoscopies during a 10-year period were retrospectively reviewed. In total, 210 microlaryngoscopies of 70 adult patients were analyzed. Overall, of 295 biopsies taken 21 % showed no dysplastic alterations, 69 % showed dysplasia and 10 % showed invasive carcinoma, which had developed out of a laryngeal dysplasia. Dysplasia grades were equally distributed within the first three microlaryngoscopies (P = 0.31, P = 0.50, P = 0.55). The risk for developing laryngeal cancer out of laryngeal dysplasia showed no statistical correlation to the initial dysplasia grade (P = 0.26). On average, the malignant conversion took 127 weeks (mild dysplasia = 117 weeks; moderate dysplasia = 135 weeks; severe dysplasia = 82 weeks) (P = 0.27). Patients with laryngeal dysplasia are an inhomogeneous group and the grade of laryngeal dysplasia alone seems to be an insufficient prognostic factor for the development of laryngeal cancer.