Cancer Risk From RA, Not the Drugs Save

While it is known that rheumatoid arthritis (RA) patients may be at risk for certain cancers, the question is which cancers and is this modified by therapy. This large, US claims analysis shows RA patients were nearly 2 times more likely (than those without RA) to develop lymphoma or lung cancer and that commonly used RA treatments were also unlikely to increase cancer risk.

RA affects 24.5 million people worldwide and has been associated with increased cancer risks.

Analysis of nationwide health insurance claims data with 85.97 million enrollees over 8 years, researchers found 92 864 patients without cancers at the time of their RA diagnoses. These were matched with 68 415 non-RA persons (by sex, race, age and inferred health and economic status) to compare cancer risk of all cancer types.

Within 12 months of an RA diagnosis, RA patients were 1.21 (95% confidence interval [CI] [1.14, 1.29]) times more likely to develop any cancer; especially lymphoma OR 2.08;1.67, 2.58) and lung cancer (OR 1.69; 1.32, 2.13) being higher RA compared to the general population.

When examining the 5 most commonly used RA drugs, none of them significantly increased cancer risk compared with RA patients without that specific drug.

This study suggests that the pathophysiology of RA, rather than its treatments, is implicated in the development of certain cancers.