RESEARCH - Biologic treatment of RA and the risk of malignancy: analyses from a large US observational study

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Arthritis Rheum. 2007 Sep;56(9):2886-95.

Biologic treatment of rheumatoid arthritis and the risk of malignancy:

analyses from a large US observational study.

Wolfe F, Michaud K.

National Data Bank for Rheumatic Diseases and University of Kansas

School of Medicine, Wichita, KS 67214, USA.

OBJECTIVE: Induction of malignancy is a major concern when rheumatoid

arthritis (RA) is treated with biologic therapy. A meta-analysis of RA

biologic clinical trials found a general increased risk of malignancy,

but this risk was not found in a large observational study. We

undertook this study to assess the risk of malignancy among

biologic-treated patients in a large US observational database.

METHODS: We studied incident cases of cancer among 13,001 patients

during approximately 49,000 patient-years of observation in the years

1998-2005. Cancer rates were compared with population rates using the

US National Cancer Institute SEER (Surveillance, Epidemiology, and

End-Results) database. Assessment of the risk of biologic therapy

utilized conditional logistic regression to calculate odds ratios

(ORs) as estimates of the relative risk, further adjusted for 6

confounders: age, sex, education level, smoking history, RA severity,

and prednisone use. RESULTS: Biologic exposure was 49%. There were 623

incident cases of nonmelanotic skin cancer and 537 other cancers. The

standardized incidence ratios and 95% confidence intervals (95% CIs)

compared with SEER data were as follows: all cancers 1.0 (1.0-1.1),

breast 0.8 (0.6-0.9), colon 0.5 (0.4-0.6), lung 1.2 (1.0-1.4),

lymphoma 1.7 (1.3-2.2). Biologics were associated with an increased

risk of nonmelanotic skin cancer (OR 1.5, 95% CI 1.2-1.8) and melanoma

(OR 2.3, 95% CI 0.9-5.4). No other malignancy was associated with

biologic use; the OR (overall risk) of any cancer was 1.0 (95% CI

0.8-1.2). CONCLUSION: Biologic therapy is associated with increased

risk for skin cancers, but not for solid tumors or lymphoproliferative

malignancies. These associations were consistent across different

biologic therapies.

PMID: 17729297

http://www.ncbi.nlm.nih.gov/pubmed/17729297

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