Ankylosing spondylitis (AS), a chronic inflammatory joint disease that may lead to extra-articular (non-joint) complications, however, the disease associated cancer risk has been poorly explored.

Researchers sought to analyze a large group of people with AS to determine the overall cancer risk in AS as a background to the future introduction of new treatments. One such group of newer medications are tumor necrosis factor-alpha (TNF-a) blockers, which have been found to be helpful in AS, but their long-term risk is unknown. Dr. N. Feltelius and colleagues from the Karolinska Hospital in Stockholm, Sweden, published results in a recent issue of the Annals of Rheumatic Diseases.

Study Set-Up
All patients with AS admitted to Swedish hospitals from1965–1995 were linked through individual national registration numbers to the Swedish Cancer Register and National Death Register. The authors calculated the standardized incidence ratio of cancer risk in 6,621 people.

Results
Researchers did not find an overall increase in cancer risk in AS. Rectal cancer was less common while unspecified kidney cancer was more common. Risks for colon, renal parenchymal, and renal pelvic cancer were not significantly increased. Laryngeal cancer was more common than expected, while lung cancer was not. Risks of haematopoietic malignancies were not increased.

The authors suggest that the decreased risk of rectal cancer might be due to local application of nonsteroidal anti-inflammatory drugs (NSAIDs), and the increased risk of unspecified kidney cancer to frequent radiological pelvic examinations.

They believe that should information on disease characteristics (including the presence or non-presence of the HLA-B27 gene) be available for individual patients with cancer, the risk-benefit analysis of long term effects of strong, new treatments might be improved.

Source: “Cancer incidence among patients with ankylosing spondylitis in Sweden 1965-95; a population based cohort study.” Annals of the Rheumatic Diseases 2003; 62: 1185-1188.