Carcinoma in situ of the larynx: an evaluation of its natural clinical course

The outcome of 75 patients with severe dysplasia or carcinoma in situ of the larynx has been reviewed. The patients were divided into three groups according to treatment; Group A (16 patients) had received irradiation. Group B (24 patients) had developed invasive carcinoma less than 1 year after the diagnosis of carcinoma in situ and Group C (41 patients) had been observed for more than 1 year, receiving no treatment other than repeat biopsies. Of the latter group, 46% developed invasive carcinoma of the vocal cords, with a mean observation time of 51 months. Mean age at the onset of the disease was 66 years in patients where the epithelium returned macroscopically to normal during observation compared to 59 years in patients who developed carcinoma (P less than 0.05). This may indicate that subgroups of carcinoma in situ exist with different biological behaviour. No extra benefit was seen for the patients who received irradiation for carcinoma in situ, and close follow-up with, eventually, stripping of the epithelium is therefore advocated. Both altered anatomical site during observation and an increase in area of the lesion should be regarded as a warning signal.