Salivary gland neoplasms are uncommon, and their epidemiology in Japan has not been well described. We conducted a retrospective review of salivary gland
tumors registered in the Hiroshima
Tumor Tissue Registry over a period of 39 years. The subjects were 5015 cases ranging in age from 6 to 97 (mean, 54.3) years old. The incidence of both benign
tumors and malignant
tumors increased with age until 60-69 years and then declined. Among the 5015
salivary gland neoplasms, 3998 (80%) were benign and 1017 (20%) were malignant.
Pleomorphic adenoma (PA) was the most frequent benign
tumor (68%), followed by
Warthin tumor (26%).
Adenoid cystic carcinoma (ACC) (27%) and
mucoepidermoid carcinoma (MEC) (26%) were the two most frequent malignant
tumors. Characteristically, there was a very low incidence of polymorphous
adenocarcinoma in Japan. The average annual age-adjusted incidence rate per 100,000 population was 3.3 for benign
tumors and 0.8 for malignant
tumors. This is the large-scale multi-institutional analysis to describe the characteristics of
salivary gland neoplasms, based on the pathological tissue registry data. We hope that the present data can contribute to early diagnosis and effective treatment of salivary gland
tumors and to
cancer prevention.