Franklin J, Lunt M, Bunn D, et al. Influence of inflammatory polyarthritis on cancer incidence and survival. Arthritis Rheum 2007;56:790-8.
It has been well established the people with rheumatoid arthritis (RA) have a higher death rate than the general population. The majority of studies show a doubling of the mortality rate that most likely corresponds with the occurrence of coexisting conditions, such as cardiovascular disease.
What Problem Was Studied?
Research scientists from the United Kingdom sought to determine the rate of new cancer and mortality due to cancer among people with newly diagnosed inflammatory polyarthritis (IP). Inflammatory polyarthritis is a term given when inflammation is present in several joints, but the firm diagnosis of RA has not yet been made. Results of the study were released in the March issue of Arthritis & Rheumatism.
What Was Done In the Study?
The Norfolk Arthritis Register (NOAR) cohort, based in Norwich, UK, was used to pool together a group that met criteria for inclusion in the study. From 1990 through 1999, a total of 2,105 people from NOAR were included in the study. Data from NOAR were linked and matched through an electronic record system of the region’s only major hospital. Likewise, data from a regional cancer registry was also compared with the arthritis registry.
What Were the Study Results?
During the study period, 130 cases of cancer (excluding non-melanoma skin cancers) were identified using the hospital record linkage. Of those, 24 were excluded and 123 cases of cancer were considered in the analysis. The rate of cancer was not increased in the IP group compared with the general population of Norfolk. However, it was found that after adjusting for age, sex and site of cancer, patients with IP had a 40 percent increased risk of dying compared with the general Norfolk population with cancer.
Although it is unclear why people with IP have reduced cancer survival, the study authors offered a few possibilities. General ill health may limit the aggression of the cancer therapy chosen. High levels of rheumatoid factor and a history of smoking may increase the risk of cancer-related mortality.
What Does This Mean for People with Rheumatoid Arthritis?
Early diagnosis and treatment of cancer will always be a person’s best chance of survival. The Arthritis Foundation encourages regular cancer screening in anyone with an inflammatory form of arthritis, including rheumatoid arthritis, psoriatic arthritis or lupus.
Daniel Solomon, MD, MPH, of Brigham and Women’s Hospital and Harvard Medical School, using an Arthritis Foundation research grant, recently studied the risk of developing cancer in people with RA who take tumor necrosis factor alpha (TNF-α) medications. He found that people taking anti-TNF-α drugs had no greater risk of developing cancer than people taking methotrexate. Of these mortality findings, Dr. Solomon comments that “It would further our understanding of both RA and cancer if we could better understand the relationship between these two disease processes. It is clear that recognizing the increased mortality risk is an important step, but much work remains to be done to uncover the reasons behind the increased risk so preventive action can be taken.”