Salivary gland tumours in a northern Chinese population: a 50-year retrospective study of 7190 cases

The aims of this study were to investigate the epidemiological and clinical characteristics of epithelial salivary gland tumours in a northern Chinese population and to evaluate the current TNM classification system. A demographic and descriptive analysis of 7190 epithelial salivary gland tumours was performed. There were 4654 benign tumours and 2536 malignant tumours. The percentage of tumours located in the parotid, submandibular, sublingual, and minor salivary glands was 62.66%, 9.92%, 2.57%, and 24.85%, respectively; 22.26%, 35.76%, 92.97%, and 61.89% of the tumours, respectively, were malignant. Over 90% in the tongue and maxillary sinus were malignant. Warthin tumour, salivary duct carcinoma, and squamous cell carcinoma were predominant in males, while basal cell adenoma, myoepithelioma, and pleomorphic adenoma were predominant in females. Further, 2.55% of the tumours were in children and adolescents: 44.81% of the tumours were malignant, as opposed to 35.02% in adults. According to the 7th TNM classification, the percentages of T3 and stage III tumours were approximately 10%. Salivary gland tumours show distribution patterns according to histological type, location, and patient age and sex. The limitations of the current TNM classification of salivary gland carcinoma should be considered and revisions made.