Background/Purpose: The recent Taiwanese report has indicated an elevated risk of malignancy in RA patients¹. Etanercept, one of the tumor necrotic factor inhibitors (TNF-I) to treat severe rheumatoid arthritis (RA), has been approved in Taiwan for 10 years. Its effect in ameliorating inflammation in RA has been shown prominent. Although the potential risk of TNF-I on cancer in RA patients has been reported, the impact of TNF-I in Asian RA patients is still lacking. We used the National Health Insurance Database in Taiwan to investigate if etanercept impacts on incident cancer in RA patients.

Methods: A prospective one-to-one case-control study matched with age, gender, index day (prescription date of etanercept), RA duration (from the date of RA diagnosis to the index day), dosage and duration of methotrexate usage was conducted. Cancer incidence, including solid-tumor and hematological malignancy, was compared in RA patients between etanercept users and those who were naïve to the TNF-I. Cox proportional hazard model was used for analysis.

Results: Among the 1,931 matched pairs (3,180 women and 682 men with the mean age of 53.8 years) during a mean follow-up of 3.7 years, 36 subjects were found cancer in the case-cohort (31 solid-tumor and 5 hematologic malignancy), and 48 in the control-cohort (46 solid-tumor and 2 hematologic malignancy). The incidences of total cancer in subjects with RA duration within 1 year and 1-2 years were 37.0 x10^-3 and 11.6 x10^-3 person-years in the case-cohort, which were lower than those of 127.2 x10^-3 and 27.9 x10^-3 person-years in the control-cohort, respectively (the corresponding p=0.002 and 0.03). On the other hand, the incidences of total cancer in subjects with RA duration within 2-3 years and more than 3 years were 12.8 x10^-3 and 2.8 x10^-3 person-years in the case-cohort, which were higher than those of 6.7 x10^-3 and 1.9 x10^-3 person-years in the control-cohort, respectively (the corresponding p=0.15 and 0.35). The incidence of hematologic malignancy in the case-cohort was 0.95 x10^-3 person-years, which was 2.5 times higher than that of 0.38 x10^-3 person-years in the control-cohort (p=0.26). Although no statistically significant risk of etanercept was noted for total cancer after multivariate adjustment, hazard ratios for solid tumor and hematologic malignancy were 0.70 (95% confidence interval, 0.44-1.33) and 2.17 (0.42-11.23), respectively.

Conclusion: A potential benefit of etanercept was shown for patients with shorter RA duration by a trend of lower cancer incidence in the etanercept users compared with controls, which was contrasted to the findings noted for patients with RA duration more than 2 years. Although a trend of higher risk of hematologic malignancy for etanercept users than controls was noted in the current study, we may not conclude a significantly higher risk for RA patients received etanercept than those who received the convention treatment to develop cancer. Further investigation is needed in the future.

Reference Chen YJ, Chang YT, Wang CB, Wu CY. The risk of cancer in patients with rheumatoid arthritis: a nationwide cohort study in Taiwan. Arthritis Rheum. 2011;63(2):352-358.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/impact-of-etanercept-on-incident-cancer-in-taiwanese-patients-with-rheumatoid-arthritis/