Malignant salivary tumors--analysis of prognostic factors and survival

A group of 113 patients with malignant salivary gland tumors was retrospectively reviewed to analyze the association of clinical and histologic factors with survival. These factors were patient sex and age, tumor site, clinical stage, histologic diagnosis, tumor grade, and whether or not final surgical margins were clear. There were 57 parotid, 40 minor salivary, and 16 submandibular gland cancers. The histologic groups were mucoepidermoid carcinoma (49 patients), adenoid cystic carcinoma (31), adenocarcinoma not otherwise specified (18), acinic cell carcinoma (7), malignant mixed tumor (5), squamous cell carcinoma (2), and undifferentiated carcinoma (1). Univariate analysis of clinical factors showed that age and clinical stage significantly influenced survival. At 10 yr the predicted cumulative survival rates for Stage I, II, III, and IV tumors were 74%, 56%, 32%, and 10%, respectively. Tumor grade was the only significant histologic factor. This was most obviously reflected among patients with mucoepidermoid carcinomas. Cumulative survival at 5 yr was 94% for those with low-grade tumors and 26% for high-grade tumors. By multivariate analysis, clinical stage, age, and tumor grade remained highly significant. Analysis of patients with only Stage I and II disease demonstrated that the significant factors were patient age, tumor site, tumor grade, and whether or not surgical clearance was achieved. These results suggest that clinical stage should not be the exclusive determinant of the extent of surgery and that the selection of patients, for adjuvant therapy may be improved by an awareness of these prognostic factors.