Features and outcomes of renal cell carcinoma of native kidneys in renal transplant recipients

OBJECTIVE To outline the features and outcomes of renal cell carcinoma (RCC) in native kidneys of renal transplant recipients, who are at increased risk of developing this disease. PATIENTS AND METHODS We retrospectively studied the clinicopathological features and survival of 28 surgically treated RCCs, which developed in 24 renal transplant recipients. Features and outcomes were compared with 671 patients with RCC who had no renal transplant. RESULTS The median interval between renal transplantation and the occurrence of RCC was 5.6 years. Acquired cystic kidney disease was present in 83% of the transplanted patients. Compared with the patients with RCC and no renal transplant, RCCs of native kidneys in transplant recipients were more frequently incidental findings (92% vs 77%, P = 0.092), multifocal (39% vs 15%, P < 0.001), bilateral (17% vs 4%, P = 0.006), had lower T stages (P = 0.040), were smaller (P = 0.027), of lower grades (P = 0.010), were more frequently papillary (43% vs 19%, P = 0.019) and occurred at a significantly younger age (P = 0.022). After a median follow-up of 6.7 years, eight renal transplant recipients had died (33%), but only two deaths were due to RCC. Survival with metastatic RCC was only 4 months, if a full resection of all metastatic sites was not achieved. In multivariate analysis the presence of a renal transplant had no effect on survival. CONCLUSIONS Most RCCs in renal transplant recipients are incidental low-stage, low-grade tumours with a favourable prognosis. The outstanding pathological findings are bilateral occurrence, papillary subtype and multifocality. Prognosis of metastatic RCC is poor but might be favourable if all metastases are resected. Screening for early detection of asymptomatic RCC is advocated.