Optimizing waiting duration for renal transplants in the setting of renal malignancy: is 2 years too long to wait?

Abstract

For potential transplant recipients with a prior history of renal malignancy, no evidence-based recommendations currently exist with regard to waiting duration on dialysis. We aim to improve decision making by evaluating the impact of waiting duration on the outcomes of kidney cancer patients awaiting renal transplantation. The United States Renal Data System was used to identify patients with a known cause of end-stage renal disease (ESRD) from 1983 to 2007. Evaluation of overall survival (OS) was performed with Kaplan-Meier estimates and Cox proportional hazards models. Fine-Gray competing risk models were used to assess cancer-specific mortality (CSM) and non-cancer-specific mortality (NCSM). Of 1 374 175 patients with ESRD, 228 984 (16.7%) received transplantation. Transplant recipients with renal malignancy-associated ESRD (RM-ESRD) had longer waiting durations than those with other known causes of ESRD (2.4 versus 1.3 years; P < 0.0001). RM-ESRD patients who had shorter waiting durations (0-2 years) had better OS than those who waited longer (2+ years) (10-year OS 69.0 versus 46.7%, respectively; P < 0.0001), with similar CSM (10-year CSM 10.3 versus 10.2%, respectively; P = 0.883), whereas NCSM was worse for those with longer waiting durations (10-year NCSM 20.7 versus 44.3%, respectively; P < 0.0001). On Cox modeling, the status of RM-ESRD was not a significant predictor (P = 0.07), while longer waiting duration remained significant (P < 0.0001). We found that CSM was not affected by waiting duration, while NCSM significantly improved with shorter wait times. These findings suggest that the OS of potential transplant recipients with RM-ESRD may be improved by reducing waiting duration.