Malignant parotid tumors. Prognostic factors and optimum treatment.

A retrospective study of 271 patients with parotid carcinoma seen between 1958 and 1980 is reported. Among these were 64 (24%) mucoepidermoid tumors (all degrees of differentiation), 50 (18%) adenocarcinomas, 40 (15%) malignant mixed tumors, 39 (14%) adenoid cystic carcinomas, 37 (14%) undifferentiated, 21 (8%) acinic, and 20 (7%) squamous cell carcinomas. The proportion of advanced (T3T4) to early (T1T2) tumors was 1.7:1. At diagnosis, 42 (15%) patients had regional metastases. An analysis for prognostic factors showed that the histology, tumor stage, regional metastases (No vs. N+), age, and damage to the facial nerve all influence cause-specific survival. After multivariate analysis the tumor size and the presence of regional metastases were the two most significant factors (p less than 0.0001 and 0.004). The prognostic characteristics were similar for the 67 (25%) patients treated by surgery and for the 169 (62%) patients treated with surgery and postoperative radiotherapy. Patients treated with combined therapy had a 10-year relapse-free rate of 62% compared to 22% for those treated by surgery alone (p = 0.0005).