Incidence rates of salivary gland tumors: results from a population-based study

Salivary gland tumors are uncommon, and their epidemiology has not been well described. We conducted a descriptive epidemiologic study of parotid, submaxillary, and sublingual gland tumors newly diagnosed in Jefferson County, Alabama, hospitals from 1968 to 1989. Incidence rates were estimated with a population-based subset of cases diagnosed during the years 1979 to 1980, 1983 to 1984, or 1987 to 1988. Among 248 incident cases, 84.3% were benign and 15.7% were malignant. Eighty-six percent of cases arose in the parotid gland, and 14% arose in the submaxillary gland. No sublingual gland tumor was identified. The benign mixed tumor was the most frequent tumor (65.6%), followed by Warthin's tumor (29.2%). Mucoepidermoid carcinoma was the most frequent malignant tumor (51.3%). The average annual age-adjusted incidence rate per 100,000 was 4.7 for benign tumors and 0.9 for malignant tumors. Incidence rates for both benign and malignant tumors increased with age until ages 65 to 74 years and then declined. Benign mixed tumors occurred more frequently in female patients, whereas Warthin's tumors and malignant tumors occurred more frequently in male patients (P < 0.05). Warthin's tumor was rare in black patients (P < 0.001). We conclude that salivary gland tumors are an uncommon but epidemiologically diverse group of tumors. Their causes are also likely to differ.