Incidences and oncological outcomes of urothelial carcinoma in kidney transplant recipients

Purpose: We investigated to determine if there is an increased rate of urothelial carcinoma (UC) in kidney transplant (KT) recipients and to compare oncological outcomes of UC in KT recipients with non-KT patients. Patients and methods: Among 2,186 patients who underwent KT in our institute, nine patients developed UC after KT in our center. Age-standardized rates (ASRs) were calculated to compare incidence rates of UC between KT patients and the general population. Additional five patients who underwent KT at other hospitals and received UC treatment at our center were included, thus a total of 14 KT patients were compared with non-KT patients in the aspect of the treatment outcomes of bladder cancer and upper urinary tract UC (UTUC) by using generalized estimating equation (GEE). Results: The ASRs of bladder cancer and UTUC in KT recipients were 25.5 and 129.5 times higher than that of the general population. Although there was no difference in bladder cancer-specific survival rates (P-value 0.1186), however, progression rates of bladder cancer were significantly higher in KT recipients with a relative risk of 10.53 (P-value 0.0481). There was no significant difference in UTUC recurrence, progression, and specific survival rate (P-values 0.8915, 0.8806, and 0.8116, respectively). Conclusion: Incidence of UC was much higher in KT recipients than the general population. Treatment outcomes for UC in KT recipients were not inferior to those of non-KT patients, except for the progression of bladder cancer. Special attention should be paid to screening and treatment of UC in KT recipients.