Clinical study of subglottic carcinoma

Abstract

Recently, therapy for laryngeal carcinoma has been becoming established, particularly in the early stage. The prognosis of laryngeal carcinoma is said to be better than that of other head and neck carcinomas. Laryngeal carcinoma is divided into 3 subtypes, supraglottic, glottic and subglottic, according to origin. We analyzed the subglottic carcinomas diagnosed and treated in our department between 1972 and 1990. During that period we treated 515 cases of laryngeal carcinoma, 204 cases of the supraglottic type, 284 cases of the glottic type, and 27 cases (5.2%) of the subglottic type. The 5-year survival rate in subglottic carcinoma was 44% (T1: 83%, T2:55%, T3: 17%, T4: 0%), worse than in the other types of laryngeal carcinoma. We think that there were 2 main reasons for the worse prognosis. The first was their high rate of local recurrence after radiation therapy particularly in the early stage. Although 15 T1 and T2 patients who received full dose (65Gy) radiotherapy had a complete response, 8 patients developed local recurrence. The results of the salvage operation were good in T1 cases, but were followed by death because of metastasis or second recurrence in 2 of the 3 T2 patients. The second reason for the worse prognosis appeared to be metastasis in the advanced cases. Five (50%) T3 and T4 patients developed metastasis to the lung, mediastinum and cervical lymph nodes, resulting in death. Thus, we believe that the main therapy for subglottic carcinoma, except T1, should be surgery to obtain a better outcome, and that adjuvant chemotherapy after irradiation or neck (paratracheal) dissection with total laryngectomy should be performed in advanced cases.