The long-held belief that immunosuppressant drugs used to treat systemic lupus erythematosus (SLE) and disease activity may increase the risk of cancer was somewhat dispelled by a recent study closely examining these relationships. Researchers conducted a multinational case-cohort analysis involving 75 patients with SLE and lymphoma (72 non-Hodgkin’s, 3 Hodgkin’s) and 4961 cancer-free control patients with SLE.1 In one group, they analyzed medical records for specific drugs (cyclophosphamide, methotrexate, azathioprine, steroids) taken by patients, while in the other group, they compared lymphoma cases with individual scores for the SLE Disease Activity Index. Of the 75 lymphoma cases reported in the study, the risk was higher in male vs female patients and increased with age, but no associations were found between SLE disease activity and lymphoma risk.
There was a suggestion of greater exposure to cyclophosphamide and higher cumulative steroids in lymphoma cases than in the cancer-free controls. However, in responding to these results, researchers counterpointed that patients with SLE exposed to cyclophosphamide still had a relatively low rate of lymphoma occurrence, with fewer than 1 new case of lymphoma per 1000 person-years of observation time (after cyclophosphamide exposure). From a practical standpoint, researchers suggest that these data offer some reassurance that most lymphoma cases in SLE are not triggered by drug exposures.
Dr. Beyzarov is scientific director for the Pharmacy Times Office of Continuing Professional Education.