Carcinomas of the minor salivary glands of the oral cavity. A population-based study from the Swedish Head and Neck Cancer Register for 2008-2018.

Background and objectives: Carcinomas of the minor salivary glands are rare with a heterogeneous pathology. This study explored the demographics, histology, treatment and survival in the Swedish population over 11 years.

Material and methods: Cases of salivary gland carcinomas in the oral cavity were extracted from the 'Swedish Head and Neck Cancer Register' (2008-2018). Statistical analyses with cross tabulation, age grouping, chi-square, the Kaplan-Meier method and log-rank tests were performed.

Results: Three hundred thirty cases were included (62% female; mean age 60 years; 83% were WHO Performance Status 0). The carcinomas were mostly stage I (57%), and the most common site was the palate with 165 tumours (50%). The most common histology was mucoepidermoid carcinoma (30%), followed by polymorphous low-grade adenocarcinoma (25%) and adenoid cystic carcinoma (24%). The distribution of histology differed between age groups. The five-year predicted overall survival rate was 83%. Most patients (89%) were treated with primary surgery.

Conclusion and significance: The demographics, histology, and survival of minor salivary gland carcinomas in the oral cavity in the Swedish population correspond well with previously published material. The demographics and histology differ from carcinomas of the major salivary glands in the same population.