Cancer risk in patients with Sjögren's syndrome in Lithuanian cohort study.

Introduction: Sjögren's syndrome (SjS) is a systemic autoimmune disease that predominantly affects the exocrine salivary and lacrimal glands, leading to the manifestation of classic symptoms-dry mouth and eyes. This study aims to analyze cancer risk by site among patients diagnosed with SjS using a Lithuanian population-based dataset.

Methods: The study cohort comprised all patients with an initial entry of Sjögren's syndrome (International Classification of Diseases Australian modification, ICD-10-AM diagnosis code M35.0) in the National Health Insurance Fund (NHIF) database, with the record of at least one prescription for antirheumatic medications in the NHIF database, recorded between 1 January 2012 and 31 December 2019. To determine cancer incidence within the cohort, we linked SjS records to the Lithuanian National Cancer Registry, incorporating data from the beginning of 2012 up to 31 December 2019, using personal identification numbers assigned to all Lithuanian citizens.

Results: In total, 29 males and 280 females diagnosed with SjS were included in the final analysis. The study found an increased risk of several cancers among female patients diagnosed with SjS. Notably, there was a statistically significant higher incidence rate of non-melanoma skin cancer (SIR 3.20, 95% CI [1.52-6.71]) and non-Hodgkin lymphoma (SIR 33.11, 95% CI [17.23-63.64]). Overall, the incidence of all cancers combined was also elevated (SIR 2.11, 95% CI [1.44-3.07]).

Conclusions: Our study shows that there is a statistically significant increased risk of non-melanoma skin cancer and non-Hodgkin lymphoma among female patients diagnosed with Sjögren's syndrome compared to the general Lithuanian population. Key Points • The study found an increased risk of melanoma and non-Hodgkin lymphoma among female patients diagnosed with SjS. • The incidence of all cancers among female patients diagnosed with SjS was elevated. • There was an increased SIR for cancer diagnosis among patients exposed to bDMARDs during the follow-up period compared to those not exposed.