People who take immunosuppressive drugs to treat lupus do not necessarily increase their cancer risk, according to a Canadian study.
Researchers said their study addresses long-standing fears of a link between lupus medication and cancer.
Previous research has suggested lupus patients have an increased risk of developing cancer, particularly lymphoma. “Treatment for lupus consists largely of immunosuppressive medications, which lower the bodys immune response,” Sasha Bernatsky, MD, PhD, the studys first author, of McGill University and the Research Institute of the McGill University Health Centre in Montreal, said in a news release.
Ann E. Clarke, co-lead on the study and the director of the MUHC lupus clinic, said the fear of developing cancer among lupus patients has been so great that some may be reluctant to take their medication and others may stop altogether.
The international study involved 75 lupus patients with lymphoma from around the world and nearly 5,000 cancer-free lupus patients as a control group. The researchers studied most of the drugs commonly used to treat SLE, including cyclophosphamide, a drug reserved for severe cases of lupus and other chronic inflammatory rheumatic diseases.
Among patients in the study, the risk for lymphoma in lupus patients exposed to cyclophosphamide was less than 0.1% per year. In addition, no clear association was observed between lupus disease activity and lymphoma risk.
“People have been wondering for a long time whether the medications were to blame, and the results are reassuring, suggesting that most lymphoma cases in SLE are not triggered by drug exposures,” Bernatsky said.
The researchers said future research will focus on what impact a lupus patients genetic profile might have on the interaction between medication exposure and lymphoma risk.
The study is scheduled for publication in the Annals of the Rheumatic Diseases. The study abstract is available at http://ard.bmj.com/content/early/2013/01/08/annrheumdis-2012-202099.abstract.