Development of Neoplasms in Pediatric Patients with Rheumatic Disease Exposed to Anti-Tumor Necrosis Factor Therapies: a Single Centre Retrospective Study

Background Anti-TNF (Tumor necrosis factor) therapy is effective in treating pediatric patients with refractory rheumatic disease. There is however a concern that anti-TNF usage may increase the risk of malignancy. Reports on specific types of malignancy in this patient population have been emerging over the past decade, but there is a need for additional malignancy reports, as these events are rare. Therefore, a retrospective chart review was performed on the biologic database of pediatric rheumatology patients at The Hospital for Sick Children (SickKids) from 1997 to 2013 for neoplasms, patient demographic information and rheumatologic treatment course. Findings 6/357 (1.68%) rheumatology patients treated with anti-TNF therapy between 1997 and 2013 developed neoplasms. One patient had two malignancies. One patient had a benign neoplasm. Cases were exposed to etanercept, infliximab or both. Neoplasms developed late after anti-TNF exposure (median 5.0 years) and infliximab treatment was associated with a shorter time to malignancy. The neoplasms identified were as follows: 2 renal clear cell carcinoma, 1 pilomatricoma, 1 nasopharyngeal carcinoma, 1 Ewing’s sarcoma, 1 hepatic T-cell lymphoma, 1 lymphoproliferative disease. Conclusions The malignancy rate at our centre is low, however more than half of the neoplasms identified were rare and unusual in the pediatric population. The 5-year malignancy-free probability for patients with juvenile idiopathic arthritis (JIA) treated with biologic therapy was 97% from our database. Long-term screening for rare neoplasms is important as part of the safety monitoring for any pediatric rheumatology patient receiving anti-TNF therapy.