Silent urothelial cancer detected by sonography after renal transplantation

OBJECTIVES: Organ transplantation increases the incidence of cancer through unclear mechanisms. In our observation, urothelial cancer happens much more frequently in Chinese people. We reviewed the detection of urothelial cancer in our series after renal transplantation. METHODS: From July 1981 to June 2005, we performed 620 renal transplantations. We do graft and native kidney sonography survey annually even if the patient is asymptomatic. During this period, 10 urothelial tumors were detected. Herein we have reviewed the findings in these cases, along with their management and outcomes. RESULTS: Moderate to severe hydronephrosis of native kidneys was observed in 14 patients, including 9 (64.3%) who had cancer including eight asymptomatic and only one with flank pain and lymph nodes metastasis succumbing in 10 months with a functioning graft. Three patients showed similar degrees of graft hydronephrosis and graft ureteral cancer was diagnosed in one. Mean time from transplantation was 5.09 years. There was a female predominance (7:3). The bladder-to-renal pelvis-to-ureter ratio was 2:5:7, which was distinct from the usual 51:3:1 distribution. In native ureter cancer, we found the left ureter more prone to develop cancer than the right (8:1). CONCLUSION: The pattern of cancer in renal transplant patients is thoroughly different from the general population, namely female predominance, with a higher incidence of ureteral and renal pelvis versus bladder cancer. In our observation, routine periodic sonography survey even in asymptomatic patients is important for urothelial tumor detection, as the incidence of cancer is surprisingly high.