TUESDAY, April 14, 2026 (HealthDay News) -- Patients with immune-mediated inflammatory diseases (IMID) have an increased cancer risk, especially in the first year after diagnosis, according to a study published online March 23 in Cancers.
Barbara Giordani, Ph.D., from the Italian National Agency for Regional Healthcare Services in Rome, and colleagues conducted a nationwide retrospective cohort study using Italian Hospital Discharge Records from patients hospitalized between Jan. 1 and Dec. 31, 2018, with five-year follow-up. Exposed patients were those with IMID, including rheumatoid arthritis (RA) and diffuse diseases of connective tissue (DDCT), and they were compared to an unexposed group including patients with primary diagnoses of injury and poisoning with no history of IMID. A total of 54,896 patients with IMID and 301,126 unexposed patients were included.
The researchers found that the IMID group had a significantly increased likelihood of cancer during the five-year follow-up (adjusted odds ratio, 1.32). Over time, there was a decrease in the adjusted odds ratio, from 1.83 in year 1 to 1.20 from the fifth year onward. In the IMID group, significant associations were seen with lung cancer, leukemia and lymphoma, bladder cancer, and melanoma (adjusted odds ratios, 1.74, 1.98, 1.48, and 1.48, respectively). An overall higher cancer risk was seen for patients with DDCT than for patients with RA (adjusted odds ratios, 1.53 and 1.20, respectively).
"Our results support the hypothesis that inflammation is a determining factor in cancer risk," lead author Antonio Giordano, M.D., Ph.D., from the University of Siena in Italy, said in a statement. "The reduction in risk over time indicates that mechanisms related to the disease, rather than drug exposure, play a central role."