Management and outcome of adenoid cystic carcinoma of the major salivary glands: the 22-year experience of a single institution.

BACKGROUND: Prognostic factors and survival rate are difficult to determine for adenoid cystic carcinoma(AdCC) of salivary glands. AIMS/OBJECTIVES: To clarify the clinical characteristics of AdCC and examine factors associated with recurrence and prognosis by histopathological grade classification. MATERIALS AND METHODS: Twenty-five patients with AdCC of the parotid gland and 10 patients with AdCC of the submandibular gland were included. We classified AdCC histopathologically by the proportion of solid components. Clinical features, fine-needle aspiration cytology (FNAC), and patient outcomes were examined according to grade. Factors associated with local recurrence and distant metastases were examined. RESULTS: Age was significantly higher in the grade III group than in the grade I group. The grade III group had significantly higher proportions of patients with cN+, pN+, and perineural invasion. In FNAC, lower-grade groups showed higher rates of correct histopathological type. Five-year disease-specific survival and disease-free survival rates were significantly lower in the grade III than in the grade I. Distant metastases were more common among patients with high-stage and perineural invasion. CONCLUSIONS: Five-year survival is significantly worse in patients with grade III.