Prognosis of Kidney Transplant Recipients With Pretransplantation Malignancy: A Nationwide Population-Based Cohort Study in Taiwan.

OBJECTIVE:The objective of this study was to evaluate the prognosis of kidney transplant recipients with pretransplantation malignancy and the incidence of recurrent malignancy in kidney transplant recipients using claims data from Taiwan's universal health insurance program. METHOD:A total of 4350 transplant recipients were retrospectively analyzed. The rates of pretransplantation or recurrent malignancy, which was defined by their inclusion in the catastrophic illness patient registry using the International Classification of Diseases, 9th Revision, were evaluated. Cox proportional hazard regression and Kaplan-Meier curves were used for the analyses. RESULTS:In total, there were 4350 kidney transplant recipients, 52.1% of patients were male, the mean age at transplantation was 45.8 years old, and the percentages of diabetes mellitus, hypertension, hepatitis B viral infection, and hepatitis C viral infection were 14%, 63.2%, 4.2%, and 2.4%, respectively. There were 95 patients (2.2%) with pretransplantation malignancy. The top 3 pretransplantation malignancies, in decreasing order, were urinary tract, kidney, and breast cancers. After kidney transplantation, 10 recipients had recurrent cancer. The overall cancer recurrence rate was 10.5%. These 10 cancers included urothelial carcinoma (n = 5), renal cell carcinoma (n = 3), breast cancer (n = 1), and thyroid cancer (n = 1). Eleven recipients had a secondary cancer. Patients without pretransplantation and post-transplantation malignancy had the best survival. Patients with pretransplantation malignancy had a greater occurrence of cancers and increased mortality regardless of whether or not they had recurrence of cancer. CONCLUSION:Our results suggest the higher risk of cancer, recurrent or secondary, and mortality after kidney transplantation. Adequate waiting time before transplantation and preventive strategies are strongly suggested in kidney transplant recipients with cancer history.