Carcinoma in situ of the larynx

A retrospective study of carcinoma in situ of the larynx at the British Columbia Cancer Institute indicates that radiotherapy, using a tumoricidal dose of Co 60, is the treatment of choice for this condition. Between 1940 and 1972, 43 patients with carcinoma in situ of the vocal cords were seen. A follow-up of five years or more was possible in 28 of these cases. Twenty-two were treated primarily with a tumoricidal dose of radiotherapy. Twenty-one of the 22 were free of disease for at least five years. This study, therefore, shows a five-year cure rate of almost 100 percent for patients treated with radiotherapy. It also brings out two further points regarding carcinoma in situ of the larynx; namely, an apparent increase in its incidence, and the presence of co-existing invasive carcinoma in some cases. We feel that since the incidence of laryngeal carcinoma has not increased, this apparent increase probably represents a greater awareness by both the pathologist and the clinician. We have also achieved more accurate diagnosis since the introduction of routine microlaryngoscopy. The single radiotherapy failure in our series was due to failure to diagnose co-existing invasive carcinoma. This would seem to be the most likely cause of similar failures reported in the literature.