ATLANTA — Lupus patients were more than 2.5 times as likely as the general population to develop blood cancers, based on data from 13,492 adults with lupus.
The risk for hematologic cancers was significantly elevated among patients with lupus. Specifically, lupus patients were more than three times as likely as the general population to develop any type of lymphoma, and more than three times as likely to develop non-Hodgkin's lymphoma. In addition, lupus patients were 1.15 times more likely than the general population to develop any cancer, said Dr. Sasha R. Bernatsky of the divisions of clinical epidemiology and rheumatology at McGill University in Montreal.
Previous studies have shown an association between systemic lupus erythematosus (SLE) and cancer, due largely to the increased risk for lymphoma. In this study, Dr. Bernatsky and her colleagues aimed for a more precise estimate of cancer rates in lupus patients, as well as stratification by age. This global effort included researchers from the Systemic Lupus International Collaborating Clinics, the Canadian Network for Improved Outcomes in SLE, and other sites around the world.
Dr. Bernatsky and her colleagues reviewed data on patients from 24 centers worldwide for an average follow-up period of 9 years, and a total of 118,359 patient-years. They identified 632 cancers during the study period.
The researchers also found a significantly increased risk of lung cancer, vulvovaginal cancer, and hepatic cancer in lupus patients, compared with the general population.
However, there was a significant decrease in the risk of hormone-sensitive cancers, including breast cancer, endometrial cancer, and ovarian cancer.
Altered clearance of viruses such as human papillomavirus might be behind the increased risk for cervical and vulvovaginal cancers in lupus patients, suggested Dr. Bernatsky. Changes in estrogen metabolism might be behind the decreased risk for hormone-sensitive cancers, although more research is needed to study these possible associations.
When the results were stratified by age, patients in the youngest age group (younger than 40 years) were significantly (1.7 times) more likely to develop any cancer compared with the general population.
Despite the increase in risk, blood cancers remain rare in lupus patients, Dr. Bernatsky noted. But the study results highlight the overall risk of cancer in lupus patients. The findings remind clinicians to counsel smoking cessation to reduce the risk of lung cancer.
The decreased risk of certain cancers such as breast cancer is good news for women with SLE “and will be an area of keen research interest in the future,” Dr. Bernatsky said.
She disclosed that she has received funding from the National Institutes of Health and research grants from the Arthritis Society of Canada.
Lupus patients have significantly higher risks for blood, lung, vulvovaginal, and hepatic cancer, said Dr. Sasha R. Bernatsky.
Source Heidi Splete/Elsevier Global Medical News