The incidence of cancer in patients with rheumatoid arthritis and a prior malignancy who receive TNF inhibitors or rituximab: results from the British Society for Rheumatology Biologics Register-Rheumatoid Arthritis

Objective. To explore the influence of TNF inhibitor (TNFi) therapy and rituximab (RTX) upon the incidence of cancer in patients with RA and prior malignancy. Methods. The study population comprised RA subjects with a prior malignancy reported to the UK national cancer registers, recruited to the British Society for Rheumatology Biologics Register from 2001 to 2013. We compared rates of first incident malignancy in a TNFi cohort, RTX cohort and synthetic DMARDs (sDMARD) cohort. Results. We identified 425 patients with a prior malignancy from 18 000 RA patients in the study. Of these, 101 patients developed a new malignancy. The rates of incident malignancy were 33.3 events/1000 person-years (py) in the TNFi cohort, 24.7 events/1000 py in the RTX cohort and 53.8 events/1000 py in the sDMARD cohort. The age- and gender-adjusted hazard ratio was 0.55 (95% CI: 0.35, 0.86) for the TNFi cohort and 0.43 (95% CI: 0.10, 1.80) for the RTX cohort in comparison with the sDMARDs cohort. The 17.0% of patients in the sDMARDs cohort had a recurrence of the same cancer in comparison with the 12.8% and the 4.3% in the TNFi and RTX cohorts, respectively. Conclusions. Although numbers are still low, it seems that patients with RA and prior malignancy selected to receive either a TNFi or RTX in the UK do not have an increased risk of future incident malignancy.