Background The exact relationship between biologics and cancer remains unclear. Despite no evidence to date of an overall increased risk of cancer on biological therapies, concerns remain about starting therapy in patients with prior malignancy.
Objectives The aim of this study was to explore the relationship between different anti-TNF and rituximab (RTX) therapy and the incidence of cancer in patients with rheumatoid arthritis (RA) and prior malignancy.
Methods The British Society for Rheumatology Biologics Register (BSRBR)-RA is a national prospective cohort study of subjects with RA starting biologic therapy. Patients receiving anti-TNF or RTX as their first biologic were included in this analysis and compared to patients who had never taken biologics. At registration, all patients were linked to the UK National Health Service Information Centre (NHS IC) which provided details of all historic cancers and any new cancers, including date of diagnosis. Analysis was limited to patients with a history of malignancy (except non melanoma skin cancer or carcinoma-in-situ) identified by the NHS IC with a diagnosis date prior to the BSRBR-RA registration date. All patients were followed by clinical and patient questionnaires every 6 months for the first 3 years and annual clinical questionnaires thereafter, in which data on drug therapy and serious adverse events were reported. Incident malignancies (IM) were defined as malignancies diagnosed after the registration date. New primaries, local recurrence and metastases were all included as incident cancers. Subjects were followed until 31/05/2013, first IM, death or switch of treatment, whichever came first. The rates of IM in the three cohorts were compared using age and gender adjusted Cox proportional hazards models.
Results In total, 3787 DMARD (recruitment: 2002-2009), 14168 biologic-naive anti-TNF (recruitment: 2001-2013) and 257 biologic-naive rituximab (recruitment: 2008-2011) treated patients were recruited. Of these, 425 patients had prior malignancy (DMARDs: 159 (4.2%); anti-TNF: 243 (1.7%); rituximab: 23 (8.9%)) (see table). Overall there was a trend towards a reduced adjusted hazard ratio of new IM for patients starting anti-TNF (HR 0.55 [95% CI 0.35, 0.87]) and rituximab (HR 0.47 [95% CI 0.11, 1.94]) compared to patients receiving DMARDs.
Conclusions Although numbers are still low, patients with RA and prior malignancy selected to receive biologic therapy in the UK do not seem to have an increased risk of future incident malignancy.
Disclosure of Interest None declared