Solid-type RCC originating from native kidneys in renal transplant recipients should be monitored cautiously

Incidental hemodialysis-related renal cell carcinoma (id-RCC) has been reported to have a good prognosis. However, we have observed rapid progression of id-RCC in some renal transplant patients. Operative indications for id-RCC detected via computed tomography (CT) immediately before renal transplantation (RTx) remain unclear. The purpose of this study was to examine the effects of immunosuppression on the progression of solid-type RCC (s-RCC) and cystic-type RCC (c-RCC). We divided 202 patients with id-RCC into four groups as follows: Group 1, s-RCC with RTx (n = 17); Group 2, c-RCC with RTx (n = 27); Group 3, s-RCC without RTx (n = 53); and Group 4, c-RCC without RTx (n = 105). Five-year cancer specific survival (CSS) rates were significantly worse in Group 1 than Group 3 (79.6% and 100%, respectively, P = 0.012), as were non-recurrence rates (NRRs) (59.2 and 100%, respectively, P < 0.001). In contrast, 5-year CSS rates were similar in Group 2 and Group 4 (100% and 95.7%, respectively, P = 0.295) as were NRR (100% and 98.7%, respectively, P = 0.230). Solid-type RCC should be removed immediately after RTx, and more carefully monitored for recurrence during follow-up.