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Short-Term Use of Immunosuppressants for Ocular Inflammation Pose No Cancer Threat

August 28, 2023

Recent research led by University of Pittsburgh and Mass Eye and Ear scientists, part of the Mass General Brigham health care system, has found that the relatively short-term use of immunosuppressant drugs to manage noninfectious ocular inflammatory conditions does not correlate with an elevated risk of cancer development. The study's results, which were published in the BMJ Oncology journal, are anticipated to offer reassurance to both patients and medical practitioners.

This reassurance pertains to instances where hesitancy in prescribing these medications might arise due to their established association with increased cancer risk in individuals who use them for extended periods or throughout their lifetime. This prolonged use is often necessary to prevent serious outcomes, such as organ rejection following transplantation.

“When we got these results, I was reassured, and I hope patients will be, too,” lead author Jeanine Buchanich, PhD, associate dean for research and associate professor of biostatistics at Pitt’s School of Public Health, said in a company news release. “Immunosuppressants are widely used and transformative for care of patients with inflammatory diseases, but the potential concern that they carry a cancer risk has forced people to make difficult decisions without enough information. Alleviating that concern with use for inflammatory diseases will help people make the treatment decision that’s right for them.”

The latest discoveries originate from the Systemic Immunosuppressive Therapy for Eye Diseases (SITE) Cohort, an initiative launched twenty years ago. The driving force behind this endeavor, John Kempen, MD, PhD, a senior scientist responsible for epidemiology in the field of ophthalmology at Mass Eye and Ear, along with his role as a professor of ophthalmology at Harvard Medical School, approached Dr. Buchanich. Dr. Buchanich directs the Center for Occupational Biostatistics and Epidemiology at Pitt Public Health. Their collaboration aimed to assess the cancer risk faced by individuals with noninfectious ocular inflammatory diseases who undergo treatment with immunosuppressants.

It is worth noting that these ocular diseases stem from immune system irregularities and are not inherently carcinogenic; however, they can lead to severe outcomes, including vision loss.

Immunosuppressive medications are a common mode of treatment for these diseases, typically administered over several months to several years.

Basics of the Study

This novel research serves as additional evidence supporting the previously established, yet limited, connection between immunosuppressant treatments and cancer risk, a linkage revealed through the SITE study consortium. A recent publication in Ophthalmology, just last month, presented their findings indicating no heightened risk of cancer-related or overall mortality in individuals utilizing widely used immunosuppressants. The study encompassed 15,938 participants from the SITE Cohort, who were monitored for an average duration of 10 years.

The BMJ Oncology study incorporated a total of 10,872 participants, effectively encompassing 84% of the initially enrolled SITE participants who resided in one of the 12 states from which the research team acquired data. This data facilitated the connection of participants to the respective cancer registries of each state. It's important to note that despite the presence of cancer incidence tracking in most states, there is no unified federal cancer registry. Each state has varying requirements and utilizes different interfaces for data sharing. Consequently, conducting extensive epidemiological cancer studies on a large scale within the United States is challenging, rendering this study that incorporates years of data from multiple states a rare occurrence.

The research team closely monitored each participant for an average duration of 10 years post their initiation of immunosuppressant medication usage. A similar observation period was established for those who did not undergo immunosuppression, aimed at identifying any instances of cancer development. The study comprehensively covered four distinct categories of immunosuppressants: TNF-inhibitors, antimetabolites, alkylating agents, and calcineurin inhibitors. Some patients were prescribed more than one type of immunosuppressant. The median duration of medication usage among patients was 1 year.

Across all four classes of immunosuppressant drugs, the researchers did not identify any indications of an elevated cancer risk among patients utilizing these medications for short-term periods, irrespective of the medication dosage.

It's worth noting that the study exclusively examined individuals with noninfectious eye diseases, and the researchers exercised caution in applying the findings to individuals with different conditions or those exposed to immunosuppressants for extended periods.

“The patients in our study actually tended to have a lower incidence of cancer than non-immunosuppressed patients, suggesting that an increased risk of overall cancer from commonly used immunosuppressants given for the short- to medium-term is very unlikely,” said Dr. Kempen. “This result is foundational for a large number of patients with inflammatory eye conditions and a broad range of patients with other inflammatory diseases.”