Purpose: This study aims to identify modifiable risk factors for de novo renal cell carcinoma (RCC) after kidney transplantation in a matched-pair approach matching for unmodifiable factors.
Patients and methods: One thousand six hundred fifty-five adults who underwent kidney transplantation in the period 1 January 2000 to 31 December 2012 were analyzed. Patients with RCC after kidney transplantation were matched in a 1:2 ratio with those without RCC using the indication for transplantation, age at transplantation (± 10 years), recipient sex (male/female), number of received transplants, living organ donor transplantation (yes/no), and time of follow-up in days as matching criteria. The paired t test was used to compare continuous variables and the Cochran-Mantel-Haenszel test for categorical variables. Multivariable conditional logistic regression modeling was used to identify independent risk factors for RCC.
Results: In matched-pair analysis, a total number of 26 incident cases with RCC after kidney transplantation could be matched. Post-transplant RCC was significantly associated with longer durations of pre-transplant hemodialysis (p = 0.007) and post-transplant immunosuppression with cyclosporine (p = 0.029) and/or mycophenolate mofetil (p = 0.020) and with larger proportions of post-transplant time on mycophenolate mofetil (p = 0.046) and/or prednisolone medication (p = 0.042). Multivariable conditional logistic regression modeling revealed a significant risk increasing multiplicative factor interaction between the duration of pre-transplant dialysis (years) and the time of prednisolone usage (percent/100). Cyclosporine A usage and mycophenolate mofetil usage were also revealed as independent, significant risk factors for RCC development.
Conclusions: Longer pre-transplant dialysis, cyclosporine-based protocols and/or intensified immunosuppression with additional mycophenolate mofetil, and larger proportions of time of prednisolone treatment during follow-up increase de novo RCC risk.
Keywords: Cyclosporine; Hemodialysis; Immunosuppression; Renal cell cancer; Renal transplantation.