From bladder to upper urinary tract: Unveiling the epidemiological dynamics of urothelial carcinoma.

677 Background: Urothelial carcinoma (UC), encompassing bladder cancer, ureteral cancer, and renal pelvic cancer, exhibits distinct epidemiological patterns. Bladder cancer is the most prevalent, accounting for 3.1% of all cancer cases globally, while upper tract urothelial carcinoma (UTUC) remains rare. Methods: This population-based study utilized cancer registry data from the Cancer Incidence in Five Continents (CI5) Plus database, covering 40 countries and regions between 2003 and 2017. Age-standardized rates (ASR) and age-specific incidence rates were calculated for bladder, ureteral, and renal pelvic cancers, stratified by country, sex, and year. Temporal trends were analyzed using Joinpoint regression to estimate annual percentage change (APC) and average annual percentage change (AAPC). Socio-Demographic Index (SDI) data were used to examine associations between socioeconomic development and UC burden. Results: In 2017, the ASR for bladder cancer among men ranged from 2.40 per 100,000 person-years in the Philippines to 35.69 per 100,000 in Italy. For women, ASRs ranged from 0.81 per 100,000 in Uganda to 7.98 per 100,000 in Denmark. The ASRs for renal pelvic cancer ranged from 0.01 per 100,000 in India to 1.46 per 100,000 in Japan for men and from 0.02 per 100,000 in India to 1.88 per 100,000 in Iceland for women. For ureteral cancer, ASRs in men ranged from 0.07 per 100,000 in India to 1.16 per 100,000 in Japan, while in women, they ranged from 0.06 per 100,000 in India to 0.41 per 100,000 in Estonia, Japan, and South Korea. The ASRs for all measures of urothelial carcinoma burden were higher for men than for women. From 2003 to 2017, bladder cancer ASRs declined in most developed countries but rose in Japan, Canada and developing countries. Conversely, ASRs for ureteral and renal pelvic cancers increased globally, except in the USA, Norway, Australia, and Thailand, where declining trends were observed. Age-specific incidence rates for all UC types generally increased with age. A significant correlation was noted between UC burden and SDI, with higher incidences associated with greater socioeconomic development. Moreover, for China, South Korea and Japan, UTUC accounts for 15.6%–21.8% of urothelial carcinomas, a proportion higher than that observed in other countries with similar SDI levels. Conclusions: Substantial geographic and socioeconomic disparities exist in UC burden. While bladder cancer incidence is decreasing in most developed countries, it is rising in developing regions. UTUC remains rare but shows a global increase. The relatively high incidence of UTUC in Eastern Asian warrants attention, and the underlying causes require further investigation. These patterns underscore the influence of socioeconomic development on UC epidemiology and highlight the need for tailored strategies to address regional disparities.