World Cancer Research Day 2023: the Bladder Cancer Epidemiology and Early Detection in Africa (BEED) study

To mark World Cancer Research Day, on 24 September, and promote this year’s theme of “integrating diversity, advancing research, and achieving equity”, the International Agency for Research on Cancer (IARC) is highlighting some of the research projects that IARC scientists are conducting to ensure that diverse populations are represented and included in cancer research, so that underrepresented groups can benefit from advances in prevention and early detection.

IARC and partner institutions are investigating the causes and risk factors associated with the development of bladder cancer in sub-Saharan Africa, as part of the Bladder Cancer Epidemiology and Early Detection in Africa (BEED) study. Bladder cancer is common in sub-Saharan Africa, but very little research on this cancer type has previously been conducted in the region. The researchers are also examining whether an inexpensive urine test, developed at IARC, could be used to improve the early detection of bladder cancer in this setting.

In most countries, almost all cases of bladder cancer are of a type called urothelial carcinoma. This is caused largely by tobacco smoking, exposure to carcinogens in the workplace, and arsenic in drinking-water. In contrast, in Africa, most bladder cancers are of a different type: squamous cell carcinoma. The IARC team have already shown that their urine test is very accurate in detecting urothelial carcinoma of the bladder. They are hoping that it can be as successful in detecting bladder squamous cell carcinoma.

Squamous cell carcinoma of the bladder is associated with chronic bladder irritation. For communities living near lakes and rivers in the Great Rift Valley, this chronic irritation is often caused by infection with a parasite, Schistosoma haematobium, which infects a vast number of people in the region.

This high prevalence of infection leads to a high incidence of bladder cancer. In Malawi, for example, bladder cancer is the sixth most common cause of cancer death. Up to 85% of squamous cell carcinomas of the bladder in Africa are associated with chronic infection with S. haematobium.

Although S. haematobium infection is a known cause of bladder cancer, it may not be the only factor that plays a role. How exactly this parasite causes cancer remains unclear, and the influence of other individual risk factors, such as tobacco smoking, alcohol consumption, and co-infection, has not been studied in this region.

It is important to find out whether and how infection with S. haematobium may interact with these other factors, enabling cancer to develop. The BEED study will provide evidence to answer this and other questions about bladder cancer in sub-Saharan Africa, potentially enabling more effective prevention policies and improved early detection of this deadly disease.