Researchers also say that out of 9,711 patients, 0.08 percent who were treated with anti-TNFs developed lymphoma, compared with 0.04 percent of the 4,845 patients in the control groups. That indicates those on the anti-TNFs have double the risk of lymphoma, but researchers stress the number is not big enough to cause alarm.

“With anti-TNF agents, although there was a small trend, it was very small and did not reach statistical significance, so at this point it is not overly concerning,” Dr. Suarez-Almazor explains. “And for most of the different tests we did it was not present, so we can conclude there is probably very little risk, if any at all, for these agents in the short term.”

In the past, there have been manyquestions, concerns and conflicting data about cancer risk among arthritis patients taking anti-TNFs. This type of biologic has been around the longest and, consequently, has been studied the most. A September 2011 report, published online in the Annals of the Rheumatic Diseases, linked anti-TNFs to higher rates of skin cancer, although two other recent studies showed no cancer connection with the medications.

In 2009, the FDA recommended adding a warning label to all anti-TNFs concerning cancer risk in response to an increase in cases of spontaneous lymphoma among children and adolescents with juvenile idiopathic arthritis, or JIA, reported to the agency’s Adverse Events Reporting system database. But a study presented at the American College of Rheumatology 2010 Scientific Meeting challenged that, instead finding that JIA itself was the reason behind the increased cancer risk, not the anti-TNFs.

It is not expected to be the last word on the subject. “Trials last a year, so our study cannot tell us what happens after five, six or seven years. But at least it is reassuring that at the beginning of treatment, there does not appear to be an increase in cancer,” Dr. Suarez-Almazor says. 

Dr. Suarez-Almazor says more studies are being done to see the effects of the medications over time. “In the short term they are safe, but we may need to study them longer as they are used in the community and by thousands of patients to recognize if they have an effect with longer duration of treatment.”

David Fox, MD, chief of the division of rheumatology at the University of Michigan Health System in Ann Arbor, says although this isn’t new data, it’s helpful to see so many previously published studies analyzed together.

“It’s reassuring in terms of the early days of having a patient on biologics, but it doesn’t speak to late, long-term consequences,” he says.

Although the data about cancer risks for those on anti-TNFs in this study isn’t statistically significant, he still believes the evidence should have clinicians assuming that anti-TNFs can increase cancer rates, and he thinks they should pass this information on to patients.

“Patients should realize that powerful medications that can control a disease as aggressive as RA do come with the risk of side effects,” Dr. Fox says. “But these risks appear to be small enough that we can be comfortable using medications in patients who need them, and the benefit is likely to be much greater than the risk.”