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.