CARCINOMA OF THE NASOPHARYNX TREATED BY RADIOTHERAPY ALONE - DETERMINANTS OF LOCAL AND REGIONAL CONTROL

Purpose: This retrospective study was conducted to review the results of treatment and to identify prognostic factors for local and regional control in a population of 378 patients with nasopharyngeal carcinoma s treated in a single institution by radiation therapy alone. Methods and Material: All patients were treated at The University of Texas M. D. Anderson Cancer Center between 1954 and 1992 following a consistent treatment philosophy but with evolving technique. There were 286 male s and 92 females with a median age of 52 years (range: 16-86 years). T he majority of the patients were Caucasian (282 patients, 75%). Thirty -two patients (8%) had one or more cranial nerve deficits. Three-fourt hs of the patients presented with AJCC Stage IV disease (T4, N0-3, 118 patients; T1-3, N2-3 164 patients). Histologically, 193 tumors (51%) were squamous cell carcinomas, 154 (41%) lymphoepitheliomas, and 31 (8 %) unclassified carcinomas. Average total dose varied with T-stage and ranged from 60.2 to 72.0 Gy. Median follow-up time was 10 years. Resu lts: For the entire population the 5-, 10-, and 20-year actuarial surv ival rates were 48, 34, and 18%, respectively, with 184 patients (49%) dying of nasopharyngeal cancer. Actuarial control rates at 5, 10, and 20 years were 71, 66, and 66% for the primary site and 84, 83, and 83 % for the neck. A total of 100 patients (26%) had local failures and 5 1 patients (13%) had regional failures with a median time to recurrenc e of 8.2 months and 13 months, respectively. Advanced T-stage, squamou s histology, and presence of cranial nerve deficits were poor prognost ic factors for local control in both univariate and multivariate analy ses. N-stage and tumor histology were significant factors for neck con trol. Treatment year, total dose within the ranges used, and duration of treatment did not have any significant effect on local or regional control. The actuarial incidence of Grade 3-5 late complications was 1 6, 19, and 29% at 5, 10, and 20 years, respectively. Twelve patients ( 3%) died of treatment-related complications; all but one fatal complic ation occurred before 1971 and the other in 1976. Conclusions: This st udy shows very good long-term local and regional control rates for nas opharyngeal carcinomas after definitive radiotherapy and establishes a benchmark for newer treatment strategies. Improvements in treatment t echnique over the years have dramatically reduced the frequency of sev ere late complications. Patients with advanced stage tumors and differ entiated squamous histology have a relatively poor prognosis when trea ted with conventional radiotherapy and are candidates for dose escalat ion or combined modality studies. (C) 1997 Elsevier Science Inc.