NEW YORK (Reuters Health) – The risk of lung cancer is increased in patients with rheumatoid arthritis, even after taking into account the effects of tobacco and asbestos exposure, according a case-control study in US military veterans.
Using a Veterans Health Administration database, Dr. Ritu Khurana, at Temple University Hospital in Philadelphia, and fellow researchers obtained medical records for approximately 480,000 patients treated between 1998 and 2004, including 7280 diagnosed with lung cancer and 8678 diagnosed with rheumatoid arthritis.
The incidence of rheumatoid arthritis was 3.4% among lung cancer patients and 1.8% among controls, the investigators report in the Journal of Rheumatology for September. After controlling for age, gender, tobacco and asbestos exposure, patients with rheumatoid arthritis were at significantly greater risk for lung cancer (adjusted odds ratio, 1.43).
The association grew stronger with age, Dr. Khurana’s group reports.
The authors note that a recent concern over the potential risks associated with anti-TNF therapy were not relevant to this population during a period when such therapy was not widely available.
In a related editorial, Dr. Henrik Kallberg, of Karolinska Institute in Stockholm, Sweden, makes the point that “it is not clear… whether the increased risk of developing cancer is due to coexisting risk factors such as smoking, to rheumatoid arthritis disease itself, to rheumatoid arthritis treatment, or simply to earlier detection of cancer because of intense medical surveillance.”
J Rheumatol 2008;35:1695-1696,1704-1708.