Newswise — The risk of invasive cancers, at least in the initial years following diagnosis, among juvenile idiopathic arthritis patients is not increased, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Philadelphia, Pa.
There are several types of JIA, all involving chronic (long-term) joint inflammation. This inflammation begins before patients reach the age of 16, may involve one or many joints, and can cause other symptoms such as fevers, rash and/or eye inflammation. Systemic onset JIA is a subset of JIA that affects about 10 percent of children with arthritis. It begins with recurrent fevers that can be 103° F or higher, often accompanied by a pink rash that comes and goes. Systemic onset JIA may cause inflammation of the internal organs as well as the joints, though joint swelling may not appear until months or even years after the symptoms begin.
Recent reports have suggested that some treatments for JIA may increase the risk of cancer in children with this disease, but there is limited information on the true risk of cancer in these children, independent of the treatment they receive.
Researchers recently examined patients at two Canadian JIA clinic registries to assess the observed cancer risk in JIA, as compared to that of the general population.
The study involved 1,168 patients with JIA, who were, on average 8.9 years old at the time of diagnosis. Over 80 percent were Caucasian, and over 67 percent were female. Information on these patients was linked to regional tumor registries to determine the occurrence of cancers between 1974 and 2006.
Patients were observed for a total of 16,396 patient-years (number of patients multiplied by number of years of observation), with an average follow up of 14 years. Based on age and sex specific general population cancer rates, researchers estimated that a total of six invasive cancers would be expected during this time period. However, none were identified – leading researchers to believe that, at least in the initial years after JIA diagnosis, the risk of invasive cancer may not be greatly increased. One limitation, according to the researchers, is the small number of minorities who participated in the study. In fact, to precisely estimate the cancer risk of JIA will require a much larger study. Because of this, researchers are hoping to complete a larger cancer study that pulls participants from multiple centers and multiple ethnicities, in order to provide more precise information about the cancer risk in JIA.
"The results so far suggest that, at least in the initial years after JIA diagnosis, the risk of invasive cancer may not be greatly increased," explains Sasha Bernatsky, MD, assistant professor, McGill University, Montreal, Quebec, and the first author of the abstract. "However, the precise cancer risk for patients with JIA, including the potential effects of medications, is still not precisely known. In general, cancer in children is very uncommon, so even a doubling of cancer risk compared to the general population probably means that a child with JIA would have much less than a 1 in 1,000 chance per year, of getting cancer during childhood."
The ACR is an organization of and for physicians, health professionals, and scientists that advances rheumatology through programs of education, research, advocacy and practice support that foster excellence in the care of people with or at risk for arthritis and rheumatic and musculoskeletal diseases. For more information on the ACR’s annual meeting, see www.rheumatology.org/annual.
Editor’s Notes: Drs. Bernatsky, Clarke, Oen, Rosenberg, and Ramsey-Goldman will present this research during the ACR Annual Scientific Meeting at the Pennsylvania Convention Center from 9 – 11 AM on Sunday, October 18 in Hall D. Ann Clarke, MD, MSc will be available for media questions and briefing at 8:30 AM on Monday, October 19 in the on-site press conference room, 109 A.
Presentation Number: 250
Malignancy in Juvenile Idiopathic Arthritis
S. Bernatsky, M, PhD , Clinical Epi, MUHC, Montreal, QC, Canada A. Rosenberg, MD, Pediatrics, Royal Univ Hosp, Saskatoon, SK Kiem G. Oen, MD, Pediatrics, University of Manitoba, Winnipeg, MB, Canada Rosalind Ramsey-Goldman, MD , Fsm # M300, Northwestern University, Chicago, IL Y. St. Pierre, MSc, Clinical Epi., MUHC, Montreal, QC, Canada E. Turnbull, RN, Clinical Epi, MUHC, Montreal, QC, Canada A. E. Clarke, MD, Allergy & Clinical Immunology, MUHC, Montreal, QC, Canada
Purpose: There is considerable interest in the increased risk of malignancy in adult rheumatoid arthritis, particularly for lymphoma and lung cancer. However, to date there have been no assessments specifically in JIA Our objectives thus were to assess the observed malignancy incidence in JIA, and compare this to the expected incidence, based on general population cancer data.
Methods: We examined cancer occurrence within the JIA clinic registries maintained at two North American pediatric rheumatology centers. The subjects in the clinic registries were linked to regional tumor registries to determine the occurrence of cancers over the observational interval, which spanned the calendar years 1974-2006. In-situ cancers were excluded. The person-years of follow-up for each subject were calculated from the date first seen at the rheumatology clinic, and the first of three possible events: death, cancer, or the end of the study interval (December 31, 2006). Pooling the data, we determined the total number of observed cancers occurring over the total person-years of observation. The total number of cancers expected to occur over the observation interval was determined by multiplying the person-years in the cohort by the geographically matched age, sex, and calendar year-specific cancer rates, and summing over all person-years.
Results: The study sample was comprised of 1,168 patients. The proportion of females in the cohort was 67.3%, and the average age at cohort entry was 8.9 years (SD=5.1). The vast majority of cohort members were Caucasian (80.5%), with the second largest racial/ethnicity group being individuals of First Nations/Inuit origin (16.9%). Subjects were observed for a total of 16,396 patient-years, with an average follow-up of 14.0 years (SD=8.1). Within this observation interval, based on regional age- and sex-appropriate cancer rates, six invasive cancers would have been expected, however, no invasive cancers occurred in our subjects.
Conclusion: No invasive cancers were demonstrated in this large sample of individuals with JIA, observed for an average of 14 years each. These data suggest that, at least in the initial years following JIA diagnosis, the risk of invasive cancers is not markedly increased. A potential limitation is the small number of specific minorities (e.g. blacks, Asians, Hispanics, etc.). Hence, study of longer-term cancer outcomes, ideally in a multi-center, multi-ethnic cohort, is of further interest.
Disclosure: S. Bernatsky, None; A. Rosenberg, None; K. G. Oen, None; R. Ramsey-Goldman, NIH, 2 ; Y. St. Pierre, None; E. Turnbull, None; A. E. Clarke, The Arthritis Society; NIH, 2 .
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