Risk of second malignant neoplasm and mortality in patients with rheumatoid arthritis treated with biological DMARDs: a Danish population-based cohort study.

Abstract

To study the risk of a second malignant neoplasm (SMN) and mortality in patients with rheumatoid arthritis (RA) with a history of a primary cancer diagnosis and treated with biological disease-modifying antirheumatic drugs (bDMARD). Among patients with RA (n=15 286) registered in the DANBIO Register during 2000-2011, 1678 had a primary cancer according to the Danish Cancer Registry. HRs for SMN and death were calculated. During follow-up there were 279 patients with RA contributing person-years to the bDMARDs use <i>before</i> their primary cancer diagnosis, 220 to the only <i>after</i>, 92 to the <i>both</i> before and after, while 1203 patients with RA contributed to the non-use strata. Ever use of bDMARDs was associated with a HR of 1.11 (95% CI 0.74 to 1.67) for developing a SMN compared with non-use (cancer site adjusted). The HR for death associated with bDMARD use <i>before</i> the primary cancer diagnosis was increased 1.53 (95% CI 1.13 to 2.09). After further adjustment for extent of the primary cancer, the HR for death was 1.20 (95% CI 0.88 to 1.63) for bDMARDs use <i>before</i> cancer, 1.36 (95% CI 0.78 to 2.39) for bDMARD use only <i>after</i> cancer and 1.22 (95% CI 0.70 to 2.13) for use <i>both</i> before and after the cancer. Among patients with RA with a history of cancer, treatment with bDMARDs was not associated with increased risk of SMN. No clear conclusion can be drawn regarding mortality in bDMARD-treated patients with RA.