A study creates a deeper understanding of the link between juvenile idiopathic arthritis, or JIA, its treatment and cancer risk: It found that treatment with tumor necrosis factor-alpha inhibitors – a type of biologic – does not appear to increase a child’s risk of cancer. But it also found that children with JIA have a more than four times higher cancer risk compared to children without JIA  – an elevated risk that doctors stress is still very small, overall.

JIA, the most common type of arthritis seen in children, affects an estimated 294,000 kids in the United States; there are several subtypes, based on the disease’s severity and number of joints affected. Because many of the most effective drugs – including biologics – can come with potentially serious side effects, such as a higher risk of infection, and patients are often put on more than one drug, treating JIA can lead some parents to wonder if the treatment is worse than the disease.

Anti-TNFs and Black Box Warnings

The first biologic drug to be FDA-approved, in 1998, was etanercept, or Enbrel, a tumor necrosis factor-alpha inhibitor – alternately called TNF inhibitor or anti-TNF. It was approved for use in children with JIA in 1999. Etanercept, like the other anti-TNFs that followed, works by suppressing parts of the immune system, which goes awry and attacks a person’s own body in autoimmune conditions like rheumatoid arthritis, or RA, as well as ankylosing spondylitis, psoriatric arthritis and JIA. Biologics, like the anti-TNF etanercept, are used to control disease, prevent joint destruction and induce remission.

In 2009, amid case reports of cancer among children and adolescents using anti-TNFs, the FDA issued a “black box” warning stating that “lymphomas and other malignancies” have been reported in those treated with anti-TNFs.

But whether anti-TNFs are linked to a higher risk of cancer, among both adults and children, is a controversial issue: large analyses, one published in 2009 and two in 2011, found no increased risk of cancer with TNF inhibitors yet, a meta-analysis published in September 2011 linked TNF inhibitors to a higher incidence of skin cancer, but not to an increase in the risk of other cancers, in adult RA patients.  

Good News and Bad News for Parents

The newest study, finding that anti-TNF use in children with JIA does not appear to be linked to a higher cancer rate, was published online in February in the journal Arthritis & Rheumatism. The data were originally presented at the 2010 American College of Rheumatology Annual Scientific Meeting.