Unusual presentation of upper urinary tract urothelial carcinoma in Taiwan: Direct comparison from Taiwan-Japan UTUC Collaboration Cohort

Objectives To carry out a comparison of upper urinary tract urothelial carcinoma characteristics and behavior between patients in Taiwan and Japan. Methods A Taiwan urinary tract urothelial carcinoma cohort was obtained from Kaohsiung Chang Gung Memorial Hospital, and a Japan urinary tract urothelial carcinoma cohort from Hirosaki University Hospital. The inclusion criteria were urinary tract urothelial carcinoma patients who underwent radical nephroureterectomy. Those who received perioperative chemotherapy were excluded. Finally, 765 patients in the Taiwan cohort and 325 in the Japan cohort were analyzed. The end-point of this study was to study the natural course of urinary tract urothelial carcinoma within 5 years between these two groups. Results The main finding was that urinary tract urothelial carcinoma patients in Taiwan were younger (P < 0.001), more were women (P < 0.001), with low-stage disease (P < 0.001), with more chronic kidney disease (P < 0.001), with less smoking history (P < 0.001), with more bladder cancer history (P = 0.002), with more multifocal (P < 0.001) and less high-grade disease (P = 0.015), as well as less lymphovascular invasion (P < 0.001) and more squamous differentiation (P < 0.001). However, the multivariate Cox regression analysis showed no racial difference in oncologic outcome, such as intravesical recurrence, systemic recurrence or cancer-specific death in primary and propensity-matched cohorts. Bladder cancer history was found to be the most important factor predicting intravesical recurrences, whereas stage was strongly associated with systemic recurrence and cancer specific mortality. Conclusions The clinical characteristics of urinary tract urothelial carcinoma in Taiwan are significantly different from those of urinary tract urothelial carcinoma in Japan. However, there is no racial difference in stage-specific oncologic outcome after standard nephroureterectomy.