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We recently published a meta-analysis of malignancy rates reported from prospective observational studies in patients treated with tumour necrosis factor inhibitors (TNF-I).1 While there was no increase in the rates of all-site malignancy or lymphoma, there was an increased risk of non-melanoma skin cancer (NMSC) (1.45, 95% CI 1.15 to 1.76).
The skin cancer analysis included data from an abstract from the British Society for Rheumatology Biologics Register (BSRBR)2 that has since been published as a full paper with different estimates.3 In the BSRBR abstract, the adjusted HR in comparison with a control cohort of patients treated with disease-modifying antirheumatic drugs, without a prior NMSC, was 1.7 (95% CI 0.9 to 3.4).2 The updated analysis provided separate estimates for basal cell carcinoma (HR 0.95 (95% CI 0.53 to 1.71)) and squamous cell carcinoma (HR 1.16 (95% CI 0.35 to 3.84)).3
Since the updated results were substantially lower than the value reported in the BSRBR abstract, we revised our analysis to include the updated data, to investigate whether our original conclusions regarding the increased risk of skin cancer could be sustained.
In our revised analysis, the pooled risk estimate for NMSC in patients treated with TNF-I was 1.33 (95% CI 1.06 to 1.60) (figure 1).
Therefore, the revised analysis is consistent with our original conclusion that treatment with TNF-I increases the risk of NMSC; although, the lower CI bound is only just above 1.0. These revised results are still aligned with a meta-analysis of randomised controlled trials across indications; although, here the increased risk of NMSC was twofold (RR 2.02, 95% CI 1.11 to 3.95).4
Direct random effects meta-analyses were conducted in a frequentist framework using Stata V.11. The level of heterogeneity was determined using the I2 statistic.
Footnotes
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Competing interests XM has received research grants or honoraria from Bristol Myers Squibb, GSK, Pfizer and Roche; AR was an employee of Wyeth Europa and had held shares in Wyeth and currently has Pfizer share options, and has undertaken consultancy work for UCB Pharma and Pfizer; PE has received research grants or honoraria from Bristol Myers Squibb, GSK, Pfizer and Roche. This work was undertaken without external funding.
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Provenance and peer review Not commissioned; internally peer reviewed.
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Xavier Mariette, Marco Matucci-Cerinic, Karel Pavelka, Peter Taylor, Ronald van Vollenhoven, Rebecca Heatley, Claire Walsh, Richard Lawson, Alan Vaughan Reynolds, Paul Emery