Scientists found no evidence that short- to medium-term use of medications to suppress the immune system increases the risk of cancer.
For people with inflammatory diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis, the decision to use immunosuppressant drugs to help manage their condition can be a difficult one — primarily because long-term use of these medications is associated with an increased risk of cancer.
However, new research published in BMJ Oncology found evidence that taking one or more immunosuppressants — specifically TNF-inhibitors, antimetabolites, alkylating agents, and calcineurin inhibitors — for 10 years or less does not raise cancer risks.
To conduct the research, scientists from the University of Pittsburgh and Mass General Brigham's Mass Eye and Ear Clinic tracked 10,872 participants from the Systemic Immunosuppressive Therapy for Eye Diseases (SITE) Cohort for 10 years after they took immunosuppressants. The average duration of medication use was one year, and some participants took more than one immunosuppressant.
The research team also followed participants who didn't take the medications for a similar length of time.
To determine the incidences of cancer among the participants, the team examined cancer registry data from their home states.
After analyzing the data, the researchers found no evidence that short- to medium-term use of immunosuppressants increased the risk of cancer, regardless of the dose.
However, the study authors note that because the study looked specifically at participants with non-infectious eye diseases, the results may not be the same for everyone taking these immunosuppressant drugs.
Still, the findings might be generalizable to people with inflammatory conditions.
"The patients in our study actually tended to have a lower incidence of cancer than nonimmunosuppressed patients, suggesting that an increased risk of overall cancer from commonly used immunosuppressants given for the short- to medium-term is very unlikely," said lead researcher John Kempen, M.D., Ph.D., a senior scientist, and director of epidemiology for ophthalmology at Mass Eye and Ear and professor of ophthalmology at Harvard Medical School.
"This result is foundational for a large number of patients with inflammatory eye conditions and a broad range of patients with other inflammatory diseases," Kempen adds.
Moreover, the results of this study were similar to previous research published in Ophthalmology, which also found no heightened risk of cancer among individuals using common immunosuppressants, including the antimetabolites methotrexate, mycophenolate mofetil, and azathioprine, and TNF inhibitors adalimumab and infliximab, and cyclosporine.