Rheumatoid arthritis and cancer risk∙results from the Greek European prospective investigation into cancer and nutrition cohort

Abstract

To investigate the relative risk of cancer development in rheumatoid arthritis (RA) patients in Greece after taking into consideration treatment modalities. The present analysis used data on the medical history of 26 331 participants in the Greek arm of the European Prospective Investigation into Cancer and Nutrition that were collected at enrollment and thereafter during active follow-up. A history of RA and of drug treatment for the disease, as reported at baseline examination, was linked to cases of cancer reported during follow-up. A total of 91 (9.9%) patients with RA developed a cancer compared with 1542 (6.1%) patients without RA. The overall hazard ratios of all cancers increased 25% [95% confidence interval (CI): 1–54] among participants with prevalent RA, and almost all the site-specific incident cancer sites considered had rate ratios above unity. In terms of the contribution of RA medication, the hazard ratios of patients treated with salicylates was close to unity (1.07, 95% CI: 0.69–1.65), whereas those who were not treated with salicylates had a 31% (95% CI: 3–67) increased risk for cancer incidence compared with those without RA at baseline. RA patients have excess cancer risk because of either underlying complex disease pathways or treatment agents targeting immune function. Administration of salicylates appears to reduce the risk of developing malignancies.