Rheumatoid Arthritis and Cancer Risk
Rheumatoid arthritis is an autoimmune disease that causes chronic inflammation of the joints. Rheumatoid arthritis can also cause inflammation of the tissue around the joints, as well as other organs in the body. Autoimmune diseases are illnesses that occur when the body tissues are mistakenly attacked by its own immune system.
RA and cancer
People with rheumatoid arthritis are roughly twice as likely as those without the disease to develop lymphoma, which is a broad term for a variety of cancers of the lymphatic system.Researchers in Sweden conducted the largest investigation of the link between RA and lymphoma to date.
Their findings, featured in the March 2006 issue of Arthritis & Rheumatism indicate a substantially increased risk of lymphoma among patients with severe RA. Very high and prolonged inflammatory activity, not its treatment, is the major risk factor.
The research team analyzed the medical records and case histories of 378 RA patients afflicted with malignant lymphoma between 1964 and 1995 and 378 individually matched, lymphoma-free controls. Using statistical analysis, the relative risks or odds ratios for lymphoma were assessed for three different levels of overall disease activity–low, medium, or high–based on disease duration and swollen and tender joint counts.
Compared with low RA activity, medium RA activity was associated with an 8-fold increase in the risk for lymphoma. The odds ratio rose dramatically for high RA activity–to a 70-fold increase in lymphoma risk. The researchers also observed increased risks of lymphoma associated with pronounced, irreversible joint damage in the hands, feet, and knees documented in the last year before lymphoma diagnosis.