Estimate of the incidence of bladder cancer in Africa: A systematic review and Bayesian meta-analysis

Objectives To quantify the epidemiology of bladder cancer in Africa to guide a targeted public health response and support research initiatives. Methods We systematically searched publicly available sources for population-based registry studies reporting the incidence of bladder cancer in Africa between January 1980 and June 2017. Crude incidence rates of bladder cancer were extracted. A Bayesian network meta-analysis model was used to estimate incidence rates. Results The search returned 1328 studies. A total of 22 studies carried out across 15 African countries met our pre-defined selection criteria. Heterogeneity across studies was high (I-2 = 98.9%, P < 0.001). The pooled incidence of bladder cancer in Africa was 7.0 (95% credible interval 5.8-8.3) per 100 000 population in men and 1.8 (95% credible interval 1.2-2.6) per 100 000 in women. The incidence of bladder cancer was consistently higher in North Africa in both sexes. Among men, we estimated a pooled incidence of 10.1 (95% credible interval 7.9-11.9) per 100 000 in North Africa and 5.0 (95% credible interval 3.8-6.6) per 100 000 in sub-Saharan Africa. In women, the pooled incidence was 2.0 (95% credible interval 1.0-3.0) per 100 000 and 1.5 (95% credible interval 0.9-2.0) per 100 000 in North Africa and sub-Saharan Africa, respectively. Incidence rates increased significantly among men from 5.6 (95% credible interval 4.2-7.2) in the 1990s to 8.5 (95% credible interval 6.9-10.1) per 100 000 in 2010. Conclusions The present study suggests a growing incidence of bladder cancer in Africa in recent years, particularly among men and in North Africa. This study also highlights the lack of quality data sources and collection of essential clinical and epidemiological data in several African countries, and this hinders public health planning.