De novo renal cell carcinoma of native kidney in renal transplant recipients.

BACKGROUND: The 10-year risk of developing a solid malignancy is 20% for kidney transplant recipients. The goal of the current study was to investigate the epidemiology and the diagnostic and prognostic parameters associated with de novo malignancies of the native kidney among transplant recipients at the authors' institution (Department of Urology and Renal Transplantation, Hôpital Salvator, Marseille, France).

METHODS: The authors reexamined the follow-up of 933 consecutive transplant recipients at their institution between 1987 and 2003. Immunossupressive therapy was not modified in the event of malignant disease, nor was systematic radiologic monitoring of native kidneys performed. All de novo malignancies of the native kidney were included in the current analysis.

RESULTS: Among the 933 patients examined, a combined total of 12 malignancies of the native kidney were diagnosed in 11 individuals. For these 11 individuals, the average ages at transplantation and diagnosis were 42.5 and 49.1 years, respectively. Ten malignancies were discovered fortuitously, whereas two were symptomatic. Among the 10 renal echographies performed, there was 1 false-negative result. Tomodensitometry was performed in 11 cases and yielded no false-negative results. The average tumor size was 37 mm. Nephrectomy was performed in 10 cases, and biopsy was performed in 1. Among the 12 kidney malignancies encountered in the current study, there were 7 conventional cell carcinomas, 3 basophilic papillary carcinomas, and 2 chromophobic renal cell carcinomas. Half of all tumors were Furhman Grade 3 lesions, and pT1aN0M0 tumors (2003 TNM staging system) also accounted for half of all malignancies in the current cohort. Two affected transplant recipients died (one due to disease), and the remaining nine are alive without recurrence and with normal renal functioning (median follow-up, 39 months).

CONCLUSIONS: There appears to be an increased risk of malignancy of the native kidney in renal transplant recipients, with high-grade and papillary tumors being particularly common. Consequently, systematic radiologic follow-up of native kidneys must be performed for individuals who undergo kidney transplantation.