Incidence and Oncological Outcomes of Urothelial Carcinoma in Kidney Transplant Recipients
To determine if there is an increased rate of urothelial carcinoma (UC) and to compare treatment outcomes of UC in kidney transplant (KT) recipients.
A total of 2,186 patients who underwent KT in our institute from February 1995 to December 2016 were investigated for incidence analysis. Age-standardized rates (ASRs; per 100,000 persons) were calculated to compare incidence rates of UC between KT patients and the general population. Five additional patients who underwent KT at external hospitals and have UC treatment at our hospital were analyzed to investigate treatment outcome. Using a generalized estimating equation (GEE; per 100,000 person-years), treatment outcomes of bladder cancer and upper urinary tract UC (UTUC) were compared between KT patients and non-KT patients
The ASRs of bladder cancer and UTUC in KT recipients were 122.22 and 113.97, which was 25.5 times and 129.5 times higher than that of the general population. Predominance of females and UTUC was observed. When comparing treatment outcomes between KT recipients and non-KT UC patients using GEE, there was no difference in bladder cancer specific survival rates. However, bladder cancer progression rates were significantly higher in KT recipients, with a relative risk of 10.53 and p-value of 0.0481. There was no statistically significant difference in UTUC recurrence, UTUC progression, or UTUC-specific survival rate per 100,000 person-years (p-values 0.8915, 0.8806, 0.8116, respectively).
Incidence of UC was much higher in KT recipients compared to the general population, especially for female KT recipients. Furthermore, the proportion of UTUC was much higher than that of bladder cancer. Treatment outcomes for UC in KT recipients were not inferior to those of non-KT patients, except in bladder cancer progression. Special attention should be paid to UC in KT recipients, including urologic screening and active treatment.