25-Year Trends in Stage-Specific Incidence Rates for Bladder Cancer in a Large Statewide Registry

BACKGROUND: Bladder cancer (BC) is a common genitourinary malignancy with over 80,000 new cases diagnosed annually and over 17,000 associated deaths. OBJECTIVE: We review 25-years of BC incidence (1993-2017) within the state of Pennsylvania to better define incidence, geographic distribution, and trends over time. METHODS: The Pennsylvania Cancer Registry was reviewed for statewide and component county age-adjusted BC incidence rates and stage distribution. Chloropleth maps plotting statewide and county-specific incidence rates across time were created using the GeoDa statistical package. RESULTS: 93,476 cases of BC were recorded in Pennsylvania from 1993 to 2017. Age-adjusted annual rates of BC over the study interval were stable at 24.5 patients per 100,000 (range, 22.7-25.6). However, annual rates of distant disease increased from 0.5 to 1.1 patients per 100,000 (p<0.001) with an average percent change increase of 6.6% over the study interval. The annual percent distribution of distant disease doubled from 2.3% to 5.1% (p<0.001) with a greater increase in women compared to men. Chloropleth maps highlighted growing 'hot spots' of bladder cancer incidence in the northwestern, northeastern, and southeastern portions of the state. CONCLUSIONS: While BC incidence in the state of Pennsylvania has remained relatively stable over the past 25 years, a concerning increase in distant disease was observed. Geospatial investigation implicates higher risk regions. Further studies are necessary to delineate the underlying etiologies for these observations.