Background: Rheumatoid arthritis (RA) is associated with certain types of cancer. The add-on effect of biologics on cancer occurrence in long-term RA remains unknown. We aimed to investigate the relative risk of cancer development among RA patients combining biologics with traditional disease-modifying anti-rheumatic drugs (DMARDs).

Methods: We conducted a nationwide cohort study between March 2003 and December 2010 using the Taiwan National Health Insurance Research Database (NHIRD). A total of 42,263 patients with RA who received long term DMARDs were identified. The risk of newly diagnosed cancer was compared between patients taking biologics in addition to DMARDs (biologics cohort, N=4,119) and four-fold propensity score-matched control patients taking nonbiologic DMARDs only (biologics-naive cohort, N=16,476). Cumulative incidences and hazard ratios (HR) were calculated after adjusting for competing mortality. Multivariate analyses were performed using Cox proportional hazards model.

Results: The incidence rates of cancer among biologics and biologics-naive cohorts were 2.09 (95% confidence interval [CI] 1.31-2.86) and 3.25 (95% CI 2.76-3.74) per 1000 person-years, respectively (p=0.03). On modified Cox proportional hazards analysis, the risk of cancer was significantly reduced in subjects in biologics cohort (adjusted HR 0.61, 95% CI 0.40-0.94, p=0.025) in comparison with subjects in biologics-naive cohort, after adjusting for age, gender, disease duration, major co-morbidities, and prior use of DMARDs and corticosteroids. The effect of biologics was consistent across all multivariate stratified analyses; and the association between biologics use and cancer risk was independent of dosage of concomitant use of non-biological DMARDs.

Conclusion: RA patients taking biologics plus long term traditional DMARDs therapy are associated with a lower risk of cancer when compared with RA patients taking traditional DMARDs alone.

Citation Format: Yi-Ju Chen, Chun-Ying Wu, Der-Yuan Chen, Jui-Lung Shen, Hsiu J. Ho, Han-Nan Liu, Yun-Ting Chang, Ken-Nan Kuo. Addition of biologic therapy to traditional disease-modifying anti-inflammatory drugs and the risk of cancer in patients with rheumatoid arthritis: a nationwide cohort study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 255. doi:10.1158/1538-7445.AM2014-255