Increased risk of malignancy in HLA-B27-positive patients with ankylosing spondylitis requiring biologics for sustained inflammation: A long-term, single-center retrospective study.

Objectives: To assess the link between the administration of biologic disease-modifying antirheumatic drugs (bDMARDs) and the risk of malignancy in human leukocyte antigen B27 (HLA-B27)-positive patients with ankylosing spondylitis (AS) experiencing sustained inflammation.

Methods: Between 2006 and 2021, 1445 HLA-B27-positive patients with AS were retrospectively evaluated. Among them, 112 patients required bDMARD therapy. The study compared conventional therapy with bDMARDs and investigated the risk factors for developing malignancies.

Results: During 8253 patient-years of follow-up, 38 (2.6%) patients developed various malignancies, including lung, liver, breast, and colon cancer. The risk of malignancy was significantly higher in the bDMARD-treated group compared to PS-matched groups receiving conventional synthetic DMARDs (csDMARD) and non-steroidal anti-inflammatory drugs. The cumulative risk of malignancies increased significantly after 6 years of follow-up. All patients who developed malignancy after bDMARD therapy received tumor necrosis factor-α inhibitors. Requiring bDMARD therapy, requiring bDMARDs in combination with csDMARD therapy, and being diagnosed with AS after 30 years of age were independent risk factors for developing malignancy.

Conclusions: HLA-B27-positive AS patients with sustained inflammation requiring biologic therapy, particularly if diagnosed after age 30, may have an increased risk of malignancy. Regular cancer screenings are advisable for these patients while undergoing biologic treatment.