Risk of malignancy in patients with rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis under immunosuppressive therapy: a single-center experience

Systemic inflammatory rheumatic diseases are associated with an increased risk of malignancy, in particular of lymphoproliferative disorders. Chronic inflammation, due to the disease itself, generates a microenvironment able to promote cancer development, but it is still controversial whether immunosuppressive therapy may contribute to carcinogenesis. The aim of the study was to evaluate the risk of malignancy in 399 patients affected by rheumatoid arthritis (RA), psoriatic arthritis and ankylosing spondylitis, all treated with either tumor necrosis factor α-inhibitors plus disease-modifying anti-rheumatic drugs (DMARDs) or DMARDs alone. The risk of malignancy in this cohort of patients, observed in the period between 2005 and 2011 at S. Andrea Hospital-Sapienza University of Rome, was compared with that of the general Italian population, matched for age, sex, and area of residence. Fourteen (3.5 %) malignancies, five of which were hematologic, have been observed. The overall cancer risk was not significantly increased in comparison to the general population, whereas the risk of hematologic malignancies appeared significantly higher in RA patients (SIR 4.94, 95 % CI 1.35–12.64), particularly in female gender (SIR 6.9, 0.95 % CI 1.88–17.66). No significant association between therapy and malignancy was demonstrated in RA patients.