Background: The use of anti-TNF in the management of rheumatoid arthritis (RA) has been coupled with concerns about tumourigenesis. Meta-analyses of randomized controlled trial (RCT) data have not found an increased risk of solid cancer. The short duration of RCT means latent events such as cancer may be missed. The aim of this study was to determine whether anti-TNF influences risk of cancer when used in routine UK clinical practice. Methods: The analysis was conducted in the BSRBR, a national cohort study. Patients with RA starting anti-TNF (etanercept (ETA), infliximab (INF) or adalimumab (ADA)) and a biologic-naive comparison cohort taking non-biologic therapy (nbDMARD) were recruited from 2001. Subjects were followed for 5 years, until 31/12/2009, first solid cancer or death, whichever came first. Subjects with prior solid cancer identified by record linkage with the UK cancer registry (NHS-IC) were excluded. Incident cancers were identified in 3 ways; lifelong flagging with NHS-IC; 6 monthly patient and physician questionnaires for 3 years and annual physician questionnaires thereafter. The first solid cancer per subject, confirmed by histology or NHS-IC, was analysed. Cancers occurring after stopping anti-TNF were attributed to the most recent anti-TNF. Rates of cancer in anti-TNF and nbDMARD cohorts were compared using Cox models adjusted using inverse probability of treatment weighting (IPTW) for age, gender, comorbidity, RA duration, NSAID, smoking and registration year. Each anti-TNF was then compared separately to nbDMARD. Site-specific analyses were performed for sites with >=10 cancers in each cohort: colorectal, lung and female breast. Results: 386 solid cancers were confirmed: 91 in 3543 nbDMARD patients and 295 in 11719 anti-TNF (84 v 63 per 10000 person-years (pyrs)) (Table 1). After adjusting for IPTW there was no difference in risk of solid cancer between the cohorts (adjusted hazard ratio (aHR) for anti-TNF 0.88 (95% CI 0.65, 1.17)). There was no difference in sitespecific risk for anti-TNF vs nbDMARD; colorectal aHR 1.21 (0.54, 2.70), lung 0.89 (0.46, 1.74), breast 0.99 (0.51, 1.92). The risk did not vary with length of follow up. Conclusions: In patients without prior solid cancer no increase in solid cancer risk was seen in this UK cohort of RA patients treated with anti- TNF followed for up to 5 years. Additional follow up is warranted to further assess site-specific risk and allow for longer latency. (Table Presented) .
Mercer, L. K., Lunt, M., Low, A. L. S., Dixon, W. G., Watson, K. D., … Hyrich, K. L. (2014). Risk of solid cancer in patients exposed to anti-tumour necrosis factor therapy: results from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis. Annals of the Rheumatic Diseases, 74(6), 1087–1093. https://doi.org/10.1136/annrheumdis-2013-204851