A meta-analysis of the incidence of malignancy in adult patients with rheumatoid arthritis

Allison L Smitten¹ , Teresa A Simon² , Marc C Hochberg³ and Samy Suissa⁴

¹Duke University School of Medicine, Duke South, Durham, NC, 27710 USA

²Global Pharmacovigilance and Epidemiology, Bristol-Myers Squibb Company, 311 Pennington-Rocky Hill Road; Hopewell, NJ, 08534 USA

³Division of Rheumatology and Clinical Immunology, University of Maryland School of Medicine, 10 S. Pine St., MSTF 8-34; Baltimore, MD, 21201 USA

⁴Division of Clinical Epidemiology, McGill University Health Centre, Royal Victoria Hospital; 687 Pine Ave West, R4.29; Montreal, QC, H3A 1A1 Canada

author email corresponding author email

Arthritis Research & Therapy 2008, 10:R45doi:10.1186/ar2404


Published:	23 April 2008

See related editorial by Solomon and Love, http://arthritis-research.com/content/10/3/109

Abstract

Introduction

The risk of malignancies in patients with rheumatoid arthritis (RA) has raised some concern, particularly with immunosuppressive approaches to disease management.

Methods

We conducted a systematic review of the literature and meta-analysis characterizing the associated risk of overall malignancy and four site-specific malignancies (lymphoma, lung, colorectal, and breast cancer) in patients with RA. A Medline search from 1990 to 2007 was conducted using specified search terms and predefined inclusion criteria for identification of relevant observational studies that provide estimates of relative risk of malignancy associated with RA. Study-specific estimates of the relative risk, as measured by standardized incidence ratios (SIRs) and estimated in comparison with the general population, were combined using a random effects model.

Results

A total of 21 publications were identified, of which 13 reported the SIR for overall malignancy, 14 for lymphoma, 10 for colorectal, 12 for lung, and 9 for breast cancer. Compared with the general population, the overall SIR estimates suggest that RA patients have approximately a two-fold increase in lymphoma risk (SIR 2.08, 95% confidence interval [CI] 1.80 to 2.39) and greater risk of Hodgkin than non-Hodgkin lymphoma. The risk of lung cancer was also increased with an SIR of 1.63 (95% CI 1.43 to 1.87). In contrast, a decrease in risk was observed for colorectal (SIR 0.77, 95% CI 0.65 to 0.90) and breast (SIR 0.84, 95% CI 0.79 to 0.90) cancer. The SIR for overall malignancy was 1.05 (95% CI 1.01 to 1.09).

Conclusion

Patients with RA appear to be at higher risk of lymphoma and lung cancer and potentially decreased risk for colorectal and breast cancer compared with the general population.