High cumulative incidence of urinary tract transitional cell carcinoma after kidney transplantation in Taiwan

Background: Cancer is a well-documented complication after kidney transplantation. Increased incidence of bladder cancer had been reported in long-term hemodialysis patients in Taiwan. Herein, the authors report a very high cumulative incidence of transitional cell carcinoma (TCC) of the urinary tract after kidney transplantation in Taiwan. Methods: The authors retrospectively reviewed the clinical data, medical records, and outcome of 730 kidney transplant (KT) recipients. The cumulative incidence of TCC was computed. The Cox regression method was used to analysis the role of potential risk factors. Results: After a mean follow-up duration of 72.2+/-54.4 months, 69 cancers were diagnosed in 63 (8.6%) KT recipients. Of them, 30 cases (4.1%) were TCC. The cumulative incidence for TCC was 3.0% after 3 years of graft survival, increasing to 7.2% at 6 years and 17.5% at 10 years. Compared with the general population in Taiwan, the standardized mortality ratio was 398.4 (male, 192.6; female, 875.6). Painless gross hematuria was the cardinal initial symptom in 22 (73.3%) of the 30 KT recipients with TCC. Another 4 (13.3%) KT recipients with TCC presented with chronic. urinary tract infection (UTI). Bilateral nephroureterectomy with removal of bladder cuffs was performed in 18 (60%) patients. Synchronous TCC in bilateral upper urinary tracts was confirmed in 11 (36.7%) of KT recipients with TCC. The age at the time of KT, female sex, compound analgesics usage, Chinese herb usage, and underground water intake had statistical significance as risk factors (P<0.05). Conclusions: The KT recipients are at extremely high risk for TCC in Taiwan, with an incidence of 4.1%. This study indicates that hematuria and chronic UTI are the initial presentation of TCC in KT recipients. Carefully urologic screening is indicated for patients with high risk for TCC, including those with older age, compound analgesics usage, Chinese herbs usage, and underground water intake as well as women.