Adenoid cystic carcinoma of the head and neck: Incidence and survival trends based on 1973-2007 Surveillance, Epidemiology, and End Results data

Background: Adenoid cystic carcinoma (ACC) of the head and neck (ACCHN) is a rare tumor of minor salivary, parotid, and submandibular glands. The biologic behavior of the disease is poorly understood, and nonsurgical treatment strategies have yet to be standardized. The long-term prognosis continues to be guarded, with an estimated 10-year survival of <60%. Population-based studies examining ACC are scarce. The authors aimed to analyze incidence rates and survival outcomes for patients diagnosed with ACCHN using national population-based data.

Methods: Data were obtained from the US National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program. Newly diagnosed ACCHN cases reported to SEER from 1973 through 2007 were categorized according to their sex, race, age, year of diagnosis, marital status, treatment interventions, primary tumor site, and disease stage. Incidence of ACCHN and postdiagnosis survival were examined over time and compared across different demographic and disease-related categories.

Results: The authors identified 3026 patients with ACCHN. The mean age at diagnosis among those cases was 57.4 years (range, 11-99 years). Analyses of incidence data demonstrated a decline in ACCHN rates between 1973 and 2007, noted across all sexes and races with no detectable inflexion points. The overall 5-year, 10-year, and 15-year survival outcomes for ACCHN patients were 90.3%, 79.9%, and 69.2%, respectively. Females, patients with localized disease, and younger patients were found to have significantly better survival across all time periods (all comparison-specific log-rank P values <0.001). Multivariate analyses revealed better prognosis among women compared with men (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.65-0.82), among married compared with unmarried individuals (HR, 0.81; 95% CI, 0.71-0.91), with certain sites of origin and stage of disease (HR, 2.788; 95% CI, 2.36-3.29), and in those who had surgery of the primary tumor site (HR, 0.45; 95% CI, 0.37-0.54).

Conclusions: The overall incidence of ACC is declining. The noted differences in survival based on sex, marital status, site of origin, and treatment intervention require further investigation.