“It’s very difficult to determine what is innate cancer risk, and what is cancer risk that results from whatever diseases or exposures you may have had, as well as the role of these medications,” Dr. Onel says. “The fundamental problem is these cancers are rare events so it is hard to make absolute statements.”

Dr. Beukelman’s study “indicates the disease is causing most of the increased risk, with the caveat that his numbers are really too small and the follow-up period too short to say conclusively that the drugs are not adding risk on top of the disease,” says Dr. Onel. He would like to see studies of children treated with the other, newer types of biologics in addition to TNF inhibitors.

Dr. Onel also points out that the data shows increased risk of cancer due to JIA alone, even for children whose disease severity does not mandate treatment with disease modifying agents or biologic therapies.

“But is this something that a parent should lose sleep over?” asks Dr. Onel. “I would argue no. While the likelihood of cancer is higher, it is still such an uncommon occurrence.”

Says Dr. Beukelman: “The more we study, the more evidence we find that uncontrolled inflammation increases risk of infections, risk of cardiovascular disease and cancer. That is likely true for children as well. Getting JIA under proper control might benefit not only the joints, but also decrease the risk of cancer.”

Shaping the Future of Treatment

Studies that analyze large databases of patient treatment and outcome, like Dr. Beukelman’s, are critical as researchers strive to untangle the risks of JIA from the risks of the drugs used to treat it, and determine the best course of treatment for young patients.

Dr. Beukelman’s team relied on Medicaid records. Pediatric rheumatologists have also been building a large, detailed database of childhood arthritis cases through an Arthritis Foundation-supported project in collaboration with the Childhood Arthritis and Rheumatology Research Alliance, or CARRA.

“The CARRA network is so important for obtaining good data,” says Dr. Onel, “because it … ensures that patients are followed long enough so that we can really know what happens to them.” Parents of children with JIA who are interested in participating in the database, should talk to their rheumatologist or pediatric rheumatologist. Physicians register their patients and input the data, after receiving each parent's consent to participate.