Malignancies after renal transplantation in Taiwan: a nationwide population-based study

Background. Renal transplantation has been regarded as the treatment of choice for end-stage renal disease. Renal transplantation increases the risk of cancers due to longterm immunosuppression. The types of post-transplantation malignancies may vary among different geographic regions and ethnic populations. To date, large population-based studies of post-transplantation malignancies in Asian renal transplant recipients (RTRs) have rarely been reported. Methods. To investigate the patterns of post-transplantation malignancies in Chinese RTRs, we performed a nationwide population-based cohort study between 1997 and 2008 based on data from the National Health Insurance Database in Taiwan. Patterns of cancer incidence in RTRs were compared with those of the general population using standardized incidence ratios (SIRs). Results. Among the 4716 RTRs (2475 males and 2241 females; mean age 44.1 6 12.4 years) and 22 556 person-years of observation, 320 post-transplant cancers were diagnosed. The SIR of all cancers was 3.75 (95% confidence interval 3.36–4.18). Women had a higher risk than men for the development of malignancies (SIR 5.04 for women and SIR 2.88 for men). Renal, bladder and liver cancers were the most common cancers, with SIRs of 44.29, 42.89 and 5.07, respectively. When stratified by age, RTRs of young age at transplant (<20 years) had the highest risk of post-transplantation malignancies. Conclusions. This study demonstrates different patterns of malignancies after renal transplantation in Chinese RTRs, with higher incidences of kidney and bladder cancers. Physicians should be more vigilant in examining RTRs for posttransplantation malignancies especially in younger patients.