The rate of incident malignancy is 4 times higher in children who have juvenile idiopathic arthritis (JIA) than in those who do not, according to new research. The findings suggested that treatment for patients with JIA, such as tumor necrosis factor α (TNF-α) inhibitors, does not necessarily explain the development of cancer in this pediatric population.
Researchers used data from US Medicaid records from 2000 through 2005 to identify 7812 children with JIA and 2 comparator groups without JIA. One group had asthma, and the second group had attention-deficit/hyperactivity disorder. The investigators categorized patients’ treatment with methotrexate(Drug information on methotrexate) (MTX) and TNF-α inhibitors as “ever” or “never” used, although many children with JIA did not receive either treatment during the study.
Among all children with JIA, the incidence rate was 4.4 times higher for probable and highly probable malignancies than among children without JIA. The incidence of cancer was similarly increased in patients with JIA who were treated with MTX but not TNF-α inhibitors (3.9 times higher than in children without JIA). No probable or highly probable malignancies were identified in patients after any use of TNF-α inhibitors during the study period.
The investigators noted that further confirmation of the findings with large-scale and long-term investigation of the association between cancer and JIA is needed. The study was reported in Arthritis & Rheumatism, an American College of Rheumatology journal.