Meta-analysis is no substitute for a comprehensive national registry

Anti-tumor necrosis factor alpha (TNF-alpha) agents have become an established treatment option for rheumatoid arthritis (RA), but are not without risks. As TNF-alpha has a role in tumour surveillance, anti-TNF-alpha blockade could potentially increase the risk of malignancy. Recent meta-analysis by Bongartz et al. (JAMA 295:2275-2285, 2006) reported an increase in the incidence of malignancy attributed to anti-TNF-alpha antibodies, and the information has quickly and uncritically reached several secondary sources with huge effects on public perception of risks related to anti-TNF-alpha therapy. In contrast, the results from the British Society for Rheumatology Biologics Register show that in clinical practice, anti-TNF-alpha therapy in RA does not appear to increase the risk of malignancy in those patients with low risk of malignancy. We discuss the issues emerging from these published data and suggest caution against giving weight to meta-analysis of short-term drug studies.