Distinctive pattern of cancer development in kidney transplant recipients: a nationwide cohort study in South Korea

Background: Kidney transplant recipients (KTRs) are at increased risk for various cancers due to long-term immunosuppression.However, recent epidemiologic patterns in Asian populations remain understudied.This study aimed to evaluate the incidence and relative risk of cancer in Korean KTRs compared with the general population.Methods: We conducted a nationwide retrospective cohort study using the Korean National Health Insurance Service database.Adult patients (≥20 years) who underwent kidney transplantation between 2004 and 2020 were included.KTRs were compared to an age-and sex-matched control group from the general population.Cancer incidence rates were calculated, and relative risks were estimated using Cox proportional hazards models.Results: Among 22,947 KTRs and 114,735 matched general population, the overall cancer incidence was higher in KTRs (10.32 per 1,000 person-years) than in the general population (5.98 per 1,000 person-years; hazard ratio [HR], 1.56; 95% confidence interval, 1.45-1.67;p < 0.001).The risks of renal (HR, 6.64), bladder (HR, 2.56), skin (HR, 6.89), and hematologic cancers, including lymphoma (HR, 5.69), were significantly elevated in KTRs compared to the general population.Notably, the incidence of colorectal cancer (HR, 0.77) and liver cancer (HR, 0.67) was lower in KTRs.Conclusion: KTRs have a significantly elevated risk of several cancers compared to the general population, with unique patterns in the South Korean cohort.The reduced incidence of colorectal and liver cancers may reflect the impact of systematic pretransplant cancer screening.These findings support the need for individualized cancer surveillance strategies tailored to recipient risk profiles and regional healthcare systems.