Information on post-transplant malignancy and mortality risk in kidney transplant tourists remains controversial and is an important concern. The present study aimed to evaluate the incidence of post-transplant malignancy and mortality risk between tourists and domestic transplant recipients using the claims data from Taiwan's universal health insurance. A retrospective study was performed on 2394 tourists and 1956 domestic recipients. Post-transplant malignancy and mortality were defined from the catastrophic illness patient registry by using the International Classification of Diseases, 9th Revision. Cox proportional hazard regression and Kaplan-Meier curves were used for the analyses. The incidence for post-transplant de novo malignancy in the tourist group was 1.8-fold higher than that of the domestic group (21.8 vs 12.1 per 1000 person-years). The overall cancer recurrence rate was approximately 11%. The top 3 post-transplant malignancies, in decreasing order, were urinary tract, kidney, and liver cancers, regardless of the recipient type. Compared with domestic recipients, there was significant higher mortality risk in transplant tourists (adjusted hazard ratio = 1.2, 95% confidence interval: 1.0-1.5). In addition, those with either pre-transplant or post-transplant malignancies were associated with increased mortality risk. We suggest that a sufficient waiting period for patients with pre-transplant malignancies should be better emphasized to eliminate recurrence, and transplant tourists should be discouraged because of the possibility of higher post-transplant de novo malignancy occurrence and mortality.
