Using information from Medicaid records from 2000 through 2005, researchers at the University of Alabama at Birmingham compared cancer rates among 7,812 children with JIA and two groups without JIA – 652,234 children with asthma and 321,821 with attention-deficit hyperactivity disorder, or ADHD.

They found a 4.4 times higher cancer risk among all children with JIA, regardless of treatment, compared to those without JIA. The cancer risk among patients treated with methotrexate without TNF inhibitors was 3.9 times higher than children without JIA, and among children who were not exposed to immunomodulatory drugs, it was 6.9 times higher. Among patients using TNF inhibitors (etanercept, in 90 percent of cases), there were no cancers during the study period.

While it is considered one of the largest investigations into cancer rates among JIA patients related to their treatment, the study is not “definitive proof,” says lead author Timothy Beukelman, MD, associate professor of pediatrics, Division of Rheumatology, University of Alabama at Birmingham, referring to the small number of cancer cases seen in children and the relatively short follow up time of the study.

However, Dr. Beukelman says, “it appears that the TNF inhibitors are likely safer than previously suspected.”

A four-times greater cancer risk is higher than any previous reports, yet “cancer in children is very uncommon,” Dr. Beukelman says. “The overall risk of cancer for children with JIA is still very low.” He says it is possible that biologic agents will decrease the cancer risk caused by the disease through effectively decreasing inflammation that is present in JIA.

Uncontrolled JIA Is a Risk Factor, Too

“It’s important for families to realize that JIA itself can carry important risks too,” says Dr. Beukelman.

Barbara Adams, MD, chief of pediatric rheumatology at the University of Michigan at Ann Arbor, says she is not surprised about the increased cancer risk for children with JIA. “We see the same pattern in adults with RA,” she notes.

“As for many of the medications we use to control juvenile arthritis, I think they may actually reduce cancer risk because they control inflammatory damage from the disease,” says Dr. Adams, echoing Dr. Beukelman. “These medications are much better at preventing disability and loss of function in children with arthritis, compared with the limited range of medications that we had before.”

As for the risks of medications to treat JIA, “Parents are caught between rock and hard place,” says Dr. Adams, who is also on the medical advisory board for Arthritis Today. “If you want your child to be well, there are certain medications we need to use, even though there are small but definite risks involved. I try to be very clear about the risks involved in the medications I prescribe, but I also put those risks into context by explaining the risks of crippling arthritis, too.”

In an editorial accompanying the study, Kenan Onel, MD, PhD, an associate professor of pediatrics and director of the Pediatric Familial Cancer Clinic at the University of Chicago, writes that Dr. Beukelman’s findings “are at once concerning and reassuring for physicians, parents and patients.”