Treatment OF Nasopharyngeal Carcinoma With Unusual Histological Features

Purpose: To evaluate the treatment results and relapse patterns for nasopharyngeal carcinomas (NPCs) with unusual histological features. Materials and Methods: From Dec 1983 to April 1997, nine cases of carcinoma occur-ring in the nasopharynx, which were characterized by unusual histological presentations, underwent radiotherapy at the Department of Radiation Oncology, Chang Gung Memorial Hospital-Linkou. The histological diagnoses for these patients were adenoid cystic carcinoma (n= 4), poorly differentiated adenocarcinoma (n= 3), and mucoepider-moid carcinoma (n= 2). This group consisted of two females and seven males, with a median age of 41 years (range, 15 to 72). Two patients with mucoepidermoid carcinoma and one with the adenoid cystic variant underwent transpalate excision of the tumor before irradiation. All patients were treated with definite irradiation, with total dose to the nasopharynx ranging from 6480 to 7280 cGy (median, 7080). Results: The five and ten-year overall survival rates, derived using the Kaplan-Meier method, were 44.4% and 29.6%, respectively. Median survival was 2.73 years. Local recurrence occurred for six of the patients (66%). The duration to local recurrence varied from 12 to 113 months, with a median of 33 months. Two patients developed distant metastasis to lung or liver. Conclusion: Nasopharyngeal carcinomas with unusual histological features are rare. As a result, the small number of such cases diagnosed during the study period limited the statistical power of this study. Relatively advanced stage distribution and a greater proportion of local relapse after definite radiotherapy were observed, with these features probably accounting for the poor survival rate for NPC cases which are characterized by unusual histological features.