Primary diffuse large B-cell lymphoma of the major salivary glands: Increasing incidence and survival

Background: Diffuse Large B-Cell Lymphoma (DLBCL) of the major salivary glands is a rare high-grade malignancy that often presents with vague symptoms. This study aimed to evaluate its incidence and prognosis on a population level. Methods: The Surveillance, Epidemiology, and End Results database was queried for cases of major salivary gland DLBCL. Results: 896 patients had DLBCL affecting the parotid gland (78.3%) or submandibular gland (19.8%). The incidence was increasing at 1.5% (P = 0.005) per year from 1973 to 2016. 24.4% of patients underwent parotidectomy, 16% had biopsy, and the remaining provided no details of diagnostic method. Five-year diseasespecific survival increased from 59.8% to 84.0%. Late-stage disease (HR = 1.7, P = 0.003) and female sex (HR = 2.1, P = 0.018) were associated with increased risk of mortality. Conclusion: Despite the rising incidence of major salivary gland DLBCL, chemotherapy and radiation treatment has resulted in increasingly favorable survival outcomes. The otolaryngologist - head and neck surgeon continues to play a critical role in establishing the diagnosis of salivary gland DLBCL.