Specific Factors Identify Cancer Risk in Systemic Lupus Erythematosus

The following article is a part of conference coverage from the 2019 American College of Rheumatology/Association of Rheumatology Professionals (ACR/ARP) Annual Meeting, being held in Atlanta, Georgia. The team at Rheumatology Advisor will be reporting on the latest news and research conducted by leading experts in rheumatology. Check back for more from the 2019 ACR/ARP Annual Meeting.

ATLANTA — Different types of cancer that occur in patients with systemic lupus erythematosus (SLE) are associated with specific risk factors, according to research results presented at the 2019 American College of Rheumatology/Association of Rheumatology Professionals (ACR/ARP) Annual Meeting, held November 8 to 13, 2019, in Atlanta, Georgia.

Researchers studied cancer risk in the Systemic Lupus Erythematosus International Collaborating Clinics (SLICC) Inception Cohort, the largest-ever cohort of patients with clinically confirmed incident SLE, across 32 centers. Of the 1848 patients with new-onset SLE who were enrolled into the cohort between 1999 and 2011, 1668 had at least 1 follow-up visit who also comprised the cohort for the current analysis.

The SLICC malignancy study is an ongoing research effort, in which patients are followed-up yearly using standard protocol. Cancer diagnoses are recorded by examining physicians at the annual study visit and confirmed with chart review, including pathology reports.

Multivariate proportional hazard regression was performed using baseline variables for demographics (age at SLE onset, sex, race/ethnicity) and time-dependent variables for drugs (eg, corticosteroids, antimalarial drugs, and immunosuppressive drugs), smoking, and SLE Disease Activity Index-2000.

During the course of 14,215 years (mean, 8.5 years), 60 cancers occurred (incidence, 4.2 events per 1000 patient-years). The types of cancer included breast, nonmelanoma skin, lung, hematologic, melanoma, prostate, cervical, renal, gastric, head and neck, thyroid, and 1 case each of rectal, sarcoma, thymoma, and uterine cancer. Compared with one-third of patients with baseline smoking in whom cancer did not develop, nearly half of the cancer cases, including lung cancer, were associated with baseline smoking. Univariate analyses of all the cancer types suggested a higher risk for cancer among patients who were white and among those with the highest quartile of disease activity at cohort entry.

However, the overall cancer risk was mostly related to the male sex and older age at the time of SLE diagnosis, according to the multivariate proportional hazard regression. This analysis showed insignificant evidence on the effect of race/ethnicity, and the point estimate for the highest quartile of disease activity reversed to suggest a nonsignificant trend toward a lower risk for cancer.

Multivariate analyses for breast cancer demonstrated that age at SLE diagnoses remained a risk factor, and antimalarial drugs were associated with a decreased risk. However, the effect of the antimalarial drugs was not clearly observed in any other cancer type. In nonmelanoma skin cancer, both age at SLE diagnosis and cyclophosphamide use were strongly linked with cancer risk.

“Additional follow-up may allow determination of the possible effects of disease activity and drugs on cancer subtypes,” the researchers wrote.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

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Reference

Bernatsky S, Ramsey-Goldman R, Urowitz M, et al. Cancer risk in a large inception SLE cohort: effects of age, smoking, and medications. Presented at: 2019 ACR/ARP Annual Meeting; November 8-13, 2019; Atlanta, GA. Abstract 2785.