Impact of accidental discovery of renal cell carcinoma at time of renal transplantation on patient or graft survival.

Background: Renal tumors are common in the pretransplant end-stage renal disease population. Their impact on transplant outcome has not been well addressed.

Methods: This study is a retrospective follow-up observational study conducted in 258 renal transplant recipients. All patients had an ipsilateral native nephrectomy at the time of transplantation. We reviewed the histopathology of all native nephrectomies to gauge the prevalence of renal cell carcinoma (RCC) and to investigate the impact of accidental discovery of RCC on graft and patient outcome.

Results: RCC was found in 12 patients (4.7%): clear type in 9 patients, and chromophobe and combined clear and papillary type in 1 and 2 patients, respectively. There was no significant difference in human leukocyte antigen mismatch, primary immunosuppression, occurrence of rejection, graft function, and patient and graft survival between patients with or without RCC. RCC presented in the other native kidney in three patients (25%) posttransplantation and one of them developed metastasis 4 years after renal transplantation in the RCC group in comparison with eight patients in the control group (3.3%; P<0.001). The median follow-up period was 56 months for the RCC group and 65 months for the control group.

Conclusions: We found that renal transplant outcome and patient survival were not adversely affected by the presence of accidently discovered RCC at the time of transplantation. These patients seem to be at significantly higher risk of the occurrence of RCC in the remaining native kidney. Further studies are warranted to confirm our results.