The relationship between cancer and rheumatoid arthritis: still a large research agenda

The association between rheumatoid arthritis (RA) and malignancies has received increased attention in recent years. Reports suggesting that tumor necrosis factor blockers might elevate the risk of malignancy in RA patients have prompted researchers to look at the incidence of malignancies in all RA patients. In a recent issue of Arthritis Research & Therapy, Smitten and colleagues suggest that previous reports of a standardized incidence ratio close to one for malignancies in RA may reflect an increased risk for some site-specific malignancies and a reduced risk for others. Here we discuss these findings and suggest what issues could be addressed in future studies.