Maion
Arthritis Rheum 2003;48:963-970.
Increased malignant lymphoma risk observed in RA patients
Patients with rheumatoid arthritis (RA), but not their first-degree relatives, have a substantially increased risk for malignant lymphomas, according to a report in the April issue of Arthritis and Rheumatism.
"Patients with RA are at increased risk for malignant lymphomas," Dr. Karin Ekstrom, of Karolinska Institutet, Stockholm, Sweden, and colleagues note. "Both conditions display a familial aggregation, and there are reports of RA and malignant lymphomas occurring in the same families."
To examine whether the increased risk of malignant lymphomas in RA is a result of genetic or environmental risk factors common to both conditions, the team assessed the risk of malignant lymphomas in first-degree relatives of RA patients. A total of 76,527 RA patients and 70,290 of their first-degree relatives were followed for over 3 decades.
The researchers observed a significantly increased risk of malignant lymphomas among patients with RA (535 cases; standardized incidence ratio 2.00). This risk remained significantly elevated for up to 2 decades.
No increased risk of malignant lymphomas was observed among first-degree relatives without RA, "although modest and nonsignificantly elevated risk estimates were observed in subgroups," Dr. Ekstrom and colleagues note.
The overall risk of childhood cancer was not elevated among offspring, according to the investigators. However, there was a slight, nonsignificant increase in malignant lymphomas, with a significant increase in Hodgkin´s lymphoma risk (5 cases; standardized incidence 3.18).
The researchers conclude that RA patients, but not their first-degree relatives, have a substantial, possibly time-dependent, increased risk of malignant lymphomas, but not cancer overall. "This indicates that the excess of malignant lymphomas in patients with RA may be directly attributable to the inflammatory disease or its treatment, rather than to common susceptibility."
However, they add, the possibility that an environmental or genetic familial trait (perhaps for a subset including Hodgkin´s disease) may play an etiologic role in malignant lymphomas, can not be ruled out.
Reuters Health, April 24, 2003
Copyright © 2002 Reuters Limited