THE ROLE OF RADIOTHERAPY IN THE MANAGEMENT OF CARCINOMA IN-SITU OF THE GLOTTIC LARYNX

Carcinoma in situ of the glottic larynx is a rare malignancy, comprisi ng only 1% to 2% of laryngeal biopsy, The management of these lesions remains controversial. In this article, the authors present results an d analysis of the management of 20 patients having these lesions treat ed by radiotherapy. A total of 20 patients who had carcinoma in situ o f the glottis were treated with curative intent with radiotherapy at t he Veterans Administration Medical Center? Minneapolis, Minnesota, U.S .A. from November 1972 through March 1993. Before radiotherapy, eight patients had only biopsies of the glottic larynx, five had one strippi ng procedure, and seven patients had two or three shipping procedures. Of the 20 patients, 19 are available for retrospective analysis, with a minimum follow-up of 4 years and a median follow-up of 7.3 years. T reatment was given to all patients by megavoltage units (cobalt 60, 2; 4-mV linear accelerator, 18). Patients were treated using: bilateral opposed wedged 6-cm x 6-cm fields, with a dose of 1.75 Gy per fraction to a total median dose of 68.4 Gy in 40 fractions over 56 elapsed tre atment days. The Kaplan-Meier method was used for survival analy sis. The 4-year disease-free survival was 95% after irradiation. The actuar ial disease-free survival for 5 and 10 years was 95%. Surgical salvage failed in one patient who had a laryngectomy for recurrent invasive s quamous cell carcinoma at 34 months after radiotherapy. Two patients d eveloped severe shortness of breath because of laryngeal edema, which required tracheostomy. Sixteen patients reported subjective significan t improvement of their voice quality, and four reported no change. Rad iotherapy is an excellent choice for patients who have recurrent carci noma in situ after undergoing stripping procedures or for those patien ts who live too far from a medical facility to allow close follow-up a nd repetitive surgical procedures. These results are comparable to tho se of other investigators who used radiotherapy with higher dose per f raction.