Treatment of carcinoma in situ of the larynx.

: The treatment of choice for carcinoma in situ of the larynx is radiotherapy. Forty-three patients were seen with this condition between 1940 and 1972 and are now suitable for five year follow-up. Thirty-seven of these patients were treated with a tumoricidal dose of Cobalt 60. Three died in less than five years--without evidence of laryngeal disease. Of the remaining 34, all but one are free of disease for five to 17 years. The only failure in this group had co-existing invasive carcinoma. The high incidence of radiotherapy failures previously reported is probably related to the frequency of co-existing invasive carcinoma. We do not feel that there is a true increase in the incidence of carcinoma in situ in recent years. The increased frequency of diagnosis is probably due to increased awareness of the disease and the routine use of microlaryngoscopy.