Kidney Graft Urothelial Carcinoma: Results From a Multicentric Retrospective National Study

OBJECTIVE To calculate the incidence of renal graft urothelial carcinoma in renal transplant recipients in a national large retrospective cohort and to analyze circumstances of diagnosis, treatment and outcome. MATERIAL AND METHODS We conducted a national retrospective, multicenter study. Thirty two transplant centers were asked to report its cases of kidney graft tumors and the number of kidney transplantations performed since the beginning of their transplantation activity. RESULTS Between January 1988 and December 2018, 56,806 patients were transplanted in the 32 centers participating in this study. Among this cohort, 107 renal graft tumors (excluding lymphoma) were diagnosed among them 11 renal transplant recipients were diagnosed with an urothelial carcinoma in the kidney graft. The calculated incidence was 0.019%. The median patient age at the time of diagnosis was 56.7 years (49.8-60.9) and 51.4 years (47-55.7) at the time of transplantation. The median time between transplantation and diagnosis was 66.6 months (14.3-97). Before treatment, 3 patients had graft tumor biopsies revealing urothelial carcinomas, 3 patients had endoscopic retrograde uretero-pyelography showing lacunary images. Two patients had a diagnostic flexible ureteroscopy with biopsies. Total nephrectomy was performed in all cases. CONCLUSION Even though occurring in the context of immune suppression, most of these tumors seemed to have a relatively good prognosis. With regards to functional outcomes histological diagnosis should always be sought for before radical treatment of these tumors. Treatment should be a transplant nephrectomy including all the ureter with a bladder cuff to ensure optimal carcinologic control.