Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Further Defining Cancer Risk in Systemic Lupus: Updated Results in an Expanded International Multi-Centre Cohort.

Bernatsky4,  Sasha R., Clarke7,  Ann E., Petri1,  Michelle A., Urowitz14,  Murray B., Fortin15,  Paul R., Gladman16,  Dafna D., Jacobsen12,  Søren

Timonium, MD
Queen Elizabeth II Health Services Center, Halifax, NS, Canada
RI McGill Univ Health Ctr, Montreal, QC, Canada
Rigshospitalet - 4242, Copenhagen, Denmark
SUNY-Downstate Medical Center, Brooklyn, NY
The Toronto Western Hospital, Toronto, ON, Canada
Toronto Western Hospital, Toronto, ON, Canada
Toronto Western Hospital, Toronto, ON, Canada
UCL Div of Medicine, Room 331, 3rd Floor, Lund, Sweden
Univ of Manitoba, Winnipeg, MB, Canada
University Hospital, Lund, Sweden
Oakland, CA
West Penn Allegheny Health System, Pittsburgh, PA
Capital Health and Dalhousie University, Chapel Hill, NC
McGill UHC/RVH, Montreal, QC, Canada
McGill University, Montreal, Canada
McGill University Health Ctr, Montreal, QC, Canada
Montreal General Hospital, Montreal, QC, Canada
Northwestern University, Chicago, IL
Notre-Dame Hospital, M-4243, Montreal, QC, Canada

Purpose:

Our previous collaborative effort demonstrated an association between systemic lupus (SLE) and cancer, driven primarily by lymphoma risk. We aimed to more precisely estimate cancer incidence rates in SLE, compared to the general population. We also present results stratified by age group.

Methods:

We assembled an expanded multi-centre international cohort of clinically confirmed SLE patients. Patients at each center were linked to regional tumor registries to determine cancer occurrence. Standardized incidence ratios (SIRs) were calculated as the ratio of observed to expected cancers. Cancers expected were determined by multiplying 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 13,492 patients from 24 centers were observed for a total of 118,359 patient-years, with an average follow-up of 9 years. Within the observation interval, 632 cancers occurred. The data confirmed an increased risk of cancer among patients with SLE. For all cancers combined, the SIR estimate was 1.15 (95% confidence interval, 95% CI, 1.06–1.24), and for all hematologic malignancies combined, the SIR was 2.53 (95% CI 2.05–3.07). Regarding specific types of hematological malignancies, increased risk was demonstrated for all lymphomas (SIR 3.21, 95% CI 2.48–4.07) as well non-Hodgkin's lymphoma specifically (SIR 3.41, 95% CI 2.61–4.39), and for leukemia (1.69, 95% CI 1.00–2.67). We also demonstrated an increased risk of lung cancer (SIR 1.24; 95% CI 1.00–1.53), cervical cancer (SIR 1.65, 95% CI 1.09–2.41), vulvo-vaginal cancers (SIR 2.80, 95% CI 1.12–5.77), and hepatic cancer (SIR 2.18, 95% CI 1.16–3.73). Meanwhile, a significant decreased risk was seen for hormone-sensitive cancers, including breast cancer (SIR 0.70, 95% CI 0.58, 0.85), endometrial cancer (SIR 0.49, 95% CI 0.27, 0.83), and ovarian cancer (0.56, 95% CI 0.28, 0.97). When SIR estimates were stratified by age, SLE patients in the youngest age group (<40) appeared to have a particularly high relative cancer risk (compared to the general population), with an over-all cancer SIR of 1.70 (95% CI 1.34, 2.12)

Conclusion:

These results more precisely define cancer risk in SLE, highlighting a higher risk of hematological malignancies, both lymphoma and leukemia; these are being further studied in case-cohort analyses of drugs and disease activity. One additional hypothesis for the higher risk of certain events, such as cervical and vulvo-vaginal cancers, is the possibility of altered clearance of viruses (e.g. HPV). On the other hand, the lower risk of several hormone-sensitive cancers may invoke the possibility of alterations in the metabolism of estrogen and/or other hormones. Although cancers in general are more common with age, younger SLE patients have a particularly high relative cancer risk (compared to the general population).

Table: Cancer Risk in Systemic Lupus

Cancer TypeObservedExpectedSIR95% CI
Hematological9939.22.532.053.07
Non-Hodgkin Lymphoma6117.93.412.614.39
All lymphoma6720.93.212.484.07
Multiple Myeloma85.61.410.612.79
Leukemia1810.61.691.002.67
Breast112159.20.700.580.85
Ovarian1221.40.560.280.97
Cervical2716.31.651.092.41
Vulvo - Vaginal72.52.801.125.77
Endometrial1428.20.490.270.83
Lung8971.71.241.001.53
Hepatic135.92.181.163.73
Pancreatic1312.11.070.571.84
Gastric1111.30.960.481.73
Colorectal6062.50.950.731.23
Thyroid1711.71.450.842.32
Bladder2115.31.370.842.09
Prostate1218.30.650.331.14
Melanoma1316.80.770.411.32

To cite this abstract, please use the following information:
Bernatsky, Sasha R., Clarke, Ann E., Petri, Michelle A., Urowitz, Murray B., Fortin, Paul R., Gladman, Dafna D., et al; Further Defining Cancer Risk in Systemic Lupus: Updated Results in an Expanded International Multi-Centre Cohort. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :731
DOI: 10.1002/art.28499

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