Renal cell carcinoma in renal graft recipients and donors: incidence and consequence

Numerous studies have reported an increasing incidence of small renal cell carcinoma (RCC). De novo RCC in a renal allograft is a rare event and has special implications in renal transplant recipients. The objective of this study was to retrospectively evaluate the incidence of RCC in renal graft recipients and donors and to determine a procedure in cases with newly detected small renal tumors at the time of kidney preparation before transplantation.

We mailed a questionnaire to 38 German transplant clinics and received answers from 27 centers. A total of 10,997 renal graft recipients were included in the period of 1990-1998.

In 30 kidneys (0.273%) RCC was detected at the time of preparation before transplantation. There were 23 male and 3 female donors. No bilateral RCC was described. The mean age of the donors with RCC was 50.9 years (range 37-72 years). The tumors had a mean size of 2.2 cm (range 0.4-6 cm). 67% of the patients had a renal tumor smaller than 20 mm. In 26/27 centers the decision to transplant relies on the result of the immediate section for microscopic examination. 16 patients (0.145%) developed RCC 3-12 years after renal transplantation (mean 7.4 years). The mean tumor size was 2.5 cm (range 2-2.8 cm). In 50% a grade 1 and in the other 50% a grade 2 carcinoma was found.

Because of the RCC incidence in donor candidates we recommend an ultrasound screening of the native kidneys before renal explantation and an immediate preparation of the kidney surface especially in donors older than 45 years. In cases with small renal lesions we recommend an immediate section for microscopic examination before transplantation to prevent tumor implantation into an otherwise healthy patient. The frequency of RCCs after renal transplantation necessitates careful clinical and instrumental examinations in organ-transplanted recipients both before and at regular intervals after transplantation, including the patient's kidneys.