Patients with RA appear to have a higher risk of developing cancers of the lymph nodes, known as lymphomas. In the past, studies have shown that the risk of developing lymphoma appears to be greater in patients who have more severe inflammation and in those with a longer duration of RA. The reasons for this increased risk are not clear, but the effects of arthritis drugs, viruses, or increased inflammation have been blamed. Many medical studies have attempted to quantify this risk and find its cause. A few of the seminal studies in this area are reviewed here.
Researchers in Canada evaluated the health records of 1210 patients with a diagnosis of RA to determine their risk of developing lymphoma. They found a three- to fourfold increase in the rate of lymphoma in these patients as compared to other Canadian patients without arthritis. This study was published in the Journal of Clinical Epidemiology in 1993.
In a 1998 study published in the British Journal of Medicine, Swedish researchers offered evidence from a populationbased study that “immune alterations” in patients with RA appear to contribute to the development of lymphomas. In a population-based sample of 11,683 patients with RA in Sweden, these researchers identified 41 patients with lymphoma and 113 without the disease. They found that there was a strong independent association between the severity and duration of inflammatory activity and the risk of lymphoma. Because arthritis drugs such as methotrexate, azathioprine, and infliximab have been suspected to contribute to the risk of lymphoma, the researchers examined the drug treatments for all patients. They found no link between any specific drug used in RA and an increased risk of lymphoma. The Swedish investigators suggested that if inflammation contributed to the risk of developing lymphoma, then treatment of RA with anti-inflammatory medications might lower a patient's risk.
In 2004, a study published in the medical journal Arthritis and Rheumatism reaffirmed the connection between RA and lymphoma and cast doubt on the connection between arthritis drugs and this cancer. In this study of 18,572 patients with RA, researchers evaluated known and suspected risk factors for lymphoma, including age, sex, severity of RA, duration of RA, and any RA treatments received. In patients with RA, the overall risk of developing a lymphoma was twice the risk of people without RA. These investigators found that increasing age, male sex, and low educational achievement were associated with increased risk of lymphoma. Conversely, current or previous drug treatment had no effect on cancer risk.
Patients with RA should be aware that they have a slightly increased risk of developing lymphoma. Symptoms such as changes in weight, fevers, and swollen lymph nodes should be reported immediately to your physician. Those symptoms do not mean you have cancer of your lymph nodes; they can also be associated with a variety of other illnesses, including minor ailments such as colds or viruses. As in other serious illnesses, early detection and treatment of lymphoma results in improved outcomes.
Patients with RA have a slightly increased risk of developing lymphoma. Report symptoms such as changes in weight, fevers, and swollen lymph nodes immediately to your physician.