Cancer incidence and the influence of immunosuppressive agents in Korean patients with systemic lupus erythematosus: a retrospective cohort study

Background: To investigate cancer incidence and the potential influence of immunosuppressive agents in Korean systemic lupus erythematosus (SLE) patients.

Methods: We conducted a retrospective analysis utilizing data from the Korea Healthcare Bigdata Linked Platform, which integrated the National Central Cancer Registry and National Health Insurance Service databases covering the period 2008-2017. Incidence rates (IRs) per 10,000 person-years (PYs) for site-specific cancers of SLE patients were calculated using ICD-O-3 codes. Multivariable logistic regression analysis was utilized to assess the association between immunosuppressive agents and cancer development in SLE patients.

Results: A total of 10,013 predominantly female (91%) Korean SLE patients with a mean age of 36.9 ± 15.2 years were included. During a follow-up of 62,268.5 PYs, 368 patients developed cancer. The IRs per 10,000 PYs for total, solid, and hematologic cancers were 59.07, 54.09, and 5.78, respectively. The most prevalent cancers (measured in IRs per 10,000 PYs) were thyroid (17.01, 95% CI 13.78-20.25), breast (8.67, 95% CI 6.36-10.98), stomach (4.49, 95% CI 2.83-6.16), colorectal (4.17, 95% CI 2.57-5.78), and cervical (3.85, 95% CI 2.31-5.39). Approximately half (50.8%) of SLE patients with cancer were diagnosed at the localized Surveillance, Epidemiology, and End Results (SEER) stage. No statistically significant association was found between immunosuppressive agents and cancer development (Odds Ratio 1.03, 95% CI 0.80-1.34).

Conclusion: Our study shows that Korean SLE patients using immunosuppressive agents are not significantly more likely to develop cancer. Further research with extended observation is warranted to corroborate these findings.