A meta-analysis links tumor necrosis factor-alpha inhibitors, also called anti-TNFs or TNF blockers, to a higher incidence of skin cancer, but not to an increase in the risk of other cancers.

A type of biologic drug, all of which interfere with the immune system, TNF blockers are used to treat rheumatoid arthritis, or RA, as well as ankylosing spondylitis, psoriatic arthritis and polyarticular juvenile idiopathic arthritis. Drugs in this class include infliximab, or Remicade; etanercept, or Enbrel; adalimumab, or Humira; certolizumab pegol, or Cimzia; and golimumab; or Simponi.

“Doctors can be reassured that there doesn’t look like there’s an increase in [most] cancers,” says the lead author of the analysis, Xavier Mariette, MD, PhD. However, the medical community needs to be cautious about the increased risk of skin cancer – particularly for people who live in sunny climates, says Dr. Mariette, professor of rheumatology and head of the rheumatology department at Bicêtre Hospital and Paris South University, in France.

The findings, published in 2011 in the Annals of Rheumatic Diseases, add to the body of information about whether TNF blockers increase the risk of cancer, which has been an issue of much concern and debate among patients and doctors. Since biologics are relatively new – dating back to a little more than 10 years – there is no long-term data, and any cancer link could take many years to show up. Clouding the picture is the fact that people with inflammatory arthritis, especially RA, are at higher risk of developing certain cancers.

The meta-analysis pooled the results of almost 30 previously published studies and study summaries on TNF blockers and different types of cancer. Among the studies that looked at skin cancer, the researchers calculated that the risk of developing non-melanoma skin cancer was 45 percent higher among patients who received TNF blockers than those who didn’t. The risk of developing melanoma (the deadliest form of skin cancer) was 79 percent higher among patients on TNF blockers, but the results were based on only the two studies that looked at melanoma.

Among the other findings: There is no increase in cancer risk in patients who used anti-TNF drugs for longer periods or in people who had previously had cancer more than five years before..