Bladder cancer in Africa, 2010-2023: burden, geographic heterogeneity, demographic drivers, pandemic-era temporal changes, and projections to 2030.

Abstract

Purpose: To characterize the burden, temporal trends, geographic heterogeneity, demographic components, pandemic-era deviations, and projected age-standardized rates of bladder cancer across Africa.

Methods: We conducted an ecological secondary analysis of modeled Global Burden of Disease Study 2023 estimates for the GBD aggregate labeled "African Union" and 54 African country locations from 2010 to 2023. Incidence, prevalence, deaths, and disability-adjusted life-years (DALYs) were assessed as counts and age-standardized rates (ASRs) per 100,000 population for both sexes combined. Trends were summarized using estimated annual percentage changes. Incidence trajectories were descriptively grouped using dynamic time warping, and changes in counts were partitioned into population-size, age-structure, and age-specific rate components using Das Gupta decomposition. Exploratory autoregressive integrated moving average models compared GBD-estimated rates in 2020-2023 with trajectories extrapolated from 2010 to 2019. Country-specific ASRs were projected through 2030 using log-linear models.

Results: For the GBD aggregate labeled "African Union," incident cases increased from 16,357 in 2010 to 31,503 in 2023, prevalent cases from 73,806 to 147,599, deaths from 9,261 to 16,467, and DALYs from 232,414 to 415,746. Corresponding ASRs increased from 3.5 to 4.4 for incidence, 13.9 to 18.3 for prevalence, 2.2 to 2.6 for deaths, and 48.1 to 56.1 for DALYs. The highest estimated incidence ASRs in 2023 occurred in Tunisia, Malawi, Libya, Egypt, and Mali, while several countries with low estimated baseline rates had rapid relative increases. Population-size change was the largest decomposition component, accounting for 39.8%-58.8% of the increase across outcomes, with additional contributions from age structure and age-specific rates. GBD-estimated incidence, mortality, and DALY rates during 2020-2023 were above the extrapolated point forecasts; however, this exploratory analysis did not establish a causal pandemic effect. The primary projection models yielded higher fitted 2030 ASRs in a majority of countries, although results varied across training windows.

Conclusion: GBD 2023 estimates indicate an increasing but geographically heterogeneous bladder cancer burden across Africa. Population growth was the largest contributor to increasing counts, while age-structure and age-specific rate changes also contributed. Regionally tailored prevention, diagnostic and treatment capacity, and improved cancer surveillance are needed. Pandemic-era deviations and 2030 projections should be interpreted as model-dependent rather than causal or definitive forecasts.