Background: Increasing time on dialysis is an established risk factor for certain cancer types for patients on dialysis, but the relationship between the time on dialysis and cancer risk after transplantation is unclear. We aimed to determine if the length of time on maintenance dialysis before the first kidney transplantation was associated with the risk of site-specific and overall incident cancers after transplantation.
Methods: Using the Australia and New Zealand Dialysis and Transplant Registry, we assessed the association between both all cancers (except for nonmelanocytic skin cancers) and site-specific cancer incidence and the duration on dialysis before the first transplantation using adjusted Cox proportional hazards and competing risk models.
Results: Over a median follow-up of 4.4 years (interquartile range, 1.7-7.7 years), the total cumulative incidence of all cancers after the first kidney transplantation was 15.0 per 1000 patient-years. There was a linear relationship between the duration of dialysis and the risk of cancer after transplantation (Ptrend=0.02). The excess risks for lung and urinary tract cancers were highest among recipients who had been on dialysis for the longest duration before transplantation (adjusted hazard ratio [95% confidence interval], 3.32 [1.00-11.4]; P=0.05 and 2.57 [1.33-4.95]; P=0.005, respectively).
Conclusion: Increasing time on dialysis is a significant risk factor for common solid organ cancers, such as lung cancer, and urinary tract cancers in kidney transplant recipients, irrespective of age. Strategies to improve cancer surveillance among recipients who had been on dialysis for a longer time may be warranted.