Common drugs used for treating RA like Cimzia, Enbrel, Humira, Remicade, and Simponi, all inhibit a natural protein called tumor necrosis factor alpha (TNFa). TNFa plays a major role in arthritis, but it also has a large part to play in protecting the body from infections and cancer.
A 2006 study found evidence of increased cancers and serious infections in patients taking anti-TNF drugs, but later studies failed to confirm the risk.
"We are more or less sure now we won't see a really big increased risk of cancer with these medicines," University of Miami rheumatologist Ozlem Pala, MD, told WebMD. "It is definitely better than what we were afraid of. But we still have to be really cautious about the possibility of cancer risk [in patients on TNF inhibitors]."
A recent analysis of of clinical trial data found no increased cancer risk for TNF inhibitors, except for an increased risk of skin cancer. Now a new analysis of patient follow-up data confirms these findings, study leader Xavier Mariette, MD, PhD, or the Universty of Paris, tells WebMD.
"We had exactly the same results. It means there was no increased risk of cancer in patients treated with TNF inhibitors compared to [other RA drugs,] Mariette told WebMD. "It is very reassuring. But we did also observe an increased risk of non-melanoma skin cancer."
Mariette notes that anti-TNF drugs weaken part of the immune system. Such drugs are known to increase the risk of skin cancers, he says, so he is not surprised to find that anti-TNF drugs increase non-melanoma skin cancer risk by 45 percent.
"This means doctors should be cautious with these drugs in patients with high lifetime sun exposure," he said. "But patients also should be aware that non-melanoma skin cancers are easily treatable."
