The Rising Incidence of Major Salivary Gland Cancer in the United States

Abstract

We performed a population-based historical cohort study using the Surveillance, Epidemiology, and End Results (SEER) database to determine trends in the incidence of major salivary gland cancer and to evaluate the effect of sex, tumor size, histology, primary site, and extent of disease. Participants were men and women with major salivary gland cancer, diagnosed 1973–2009. The incidence of major salivary gland cancer increased from 10.4 per 1,000,000 in 1973 to 16 per 1,000,000 in 2009 (annual percent change [APC] 0.99; 95% confidence interval [CI] 0.78 to 1.20; p < 0.05). The incidence of parotid cancers increased (APC 1.13; 95% CI 0.88 to 1.39; p < 0.05) and paralleled the increase in major salivary gland cancer overall. There was an increase in the incidence of tumors measuring 0 to 2.0 cm (APC 1.99; 95% CI 0.61 to 3.38; p < 0.05), but no change in tumors measuring 2.1 to 4.0 cm (APC 1.02; 95% CI -0.46 to 2.52; p > 0.05) and tumors measuring >4 cm (APC -0.52; 95% CI -1.72 to 0.69; p > 0.05). There was an increase in the incidence of regional (APC 0.77; 95% CI 0.32 to 1.23; p < 0.05) and distant (APC 2.43; 95% CI 1.43 to 3.45; p < 0.05) disease, but not localized disease (APC 0.35; 95% CI 0 to 0.71; p > 0.05). We conclude that the incidence of major salivary gland cancer is increasing, especially small parotid tumors. The incidence of tumors with regional and distant metastasis is also increasing. These findings highlight the need for further research on the etiology of salivary gland cancer, which may reveal opportunities for further public health efforts aimed at prevention.