- Prostate cancer is the 'silent killer' of Southern African black men.
- Regular prostate cancer screening is, therefore, crucial for this group.
- Dependence on public healthcare, however, leaves many black men with reduced chances of early diagnosis.
While discussing mother and baby health at a community gathering in the rural Vhembe District of Limpopo, one of the male traditional leaders asked when we were going to do something for men.
It’s an excellent question as men’s health doesn’t receive the same attention as women’s health in the public arena. But as researchers, we are certainly doing something for men’s health. Since 2008 we have been researching prostate cancer, the "silent killer" of Southern African black men, of which many of them are unaware. As such, we set out on the journey of "dzomo", which in Tshivenda means to "give a voice".
Regular PSA screening essential
According to the latest GLOBOCON 2020 figures, men from Southern Africa are twice as likely to die from prostate cancer than the global average. Within the United States, African American men are up to five times as likely to die from prostate cancer as men of European or Asian ancestry. This places African ancestry as a significant risk factor for prostate cancer and associated mortality, along with increased age and a family history of the disease.
At the outset, we want to emphasise that regular prostate cancer PSA screening is fundamental in diagnosing cancer in an early stage as elevated levels indicate that a prostate biopsy should be done. The South African Prostate Cancer Foundation recommends that PSA measurements and digital rectal examination in black men should start after the age of 40 years and in all other men at 45. Men should know their PSA levels and testing should be available at all healthcare facilities.
While this can be expected for men on medical aid, most South African men are dependent on public healthcare facilities, of which only selected clinics offer testing. This leaves many black men in the high-risk category with reduced chances of early diagnosis for intervention. Coordinated efforts are critical to addressing this incongruity, while all populations may benefit from awareness of the disease.
Symptoms of prostate cancer can include painful emptying of the bladder and complaints about erectile dysfunction. There can also be no symptoms whatsoever, which is why annual testing, a thorough examination and history-taking are so important.
Worse in rural areas
To try and understand why men of African ancestry develop more aggressive prostate cancer, we used seed funding from the Medical Research Council and CANSA to determine the impact of this disease in South Africa. Our initial study of 837 men recruited from urological clinics across Limpopo and Gauteng, of which 522 had prostate cancer, showed Black South African men had more than twice the risk of presenting with aggressive prostate cancer compared to African Americans.
This difference was found to be worse in men from rural areas. This calls for additional research into environmental factors in our communities.
More recently we have been funded by both the Australian and USA governments to the value of R22 million to use genomic profiling and data science to identify both genetic and environmental drivers of aggressive disease within our rural communities. The project will identify patterns of exposure left within the DNA of the developing tumour. Specifically, we are intensively researching exposure patterns of chemical pollution from DDT, which is sprayed in Vhembe to control malaria. Other research has found that breast cancer in women is associated with in utero exposure to DDT. The same may apply to the development of prostate cancer.
While the use of DDT as an insecticide has been banned in many countries around the world, it is, however, sprayed as an economical method of mosquito vector control in malaria-endemic regions of South Africa. DDT is a toxic chemical and a known endocrine-disrupting chemical (EDC) as it interferes with hormones. The World Health Organization is working on finding alternatives that are not harmful to human and environmental health. In the meantime, DDT has been in use in the Vhembe region since 1945, resulting in men over 70 years having had a lifetime of exposure.
'Grassroots to cloud' approach
The SAPCS is combining demographic and lifestyle data with biochemical and genetic data to get to the bottom of what is causing lethal prostate cancer in our population. Having recruited over 2 500 men, with over 60% from the rural areas of Limpopo, critical to our research is that we have formed deep, longstanding relationships of trust within their communities, including traditional leaders and traditional healers. It is through this retained partnership with the Vhembe community that the SAPCS has more recently been in a position to attract international funding.
We are proud of our "grassroots to cloud" approach – our study is designed on the ground with the people for the people, which is then merged with state-of-the-art genomic technologies and big data analytics. While the research is always brought back to the people, with the ultimate aim to improve health outcomes for South African men, the international funders also recognise global benefits. In the United States, the Department of Defence recognised the significance for the African American population. In Australia, the National Health and Medical Research Council recognises that the knowledge gained from this project builds knowledge for all men.
Our latest study is the SAPCS Target Africa project. This will be the biggest study of its kind, including eight academic institutes from four countries – the USA, Australia, the UK and South Africa. The goal is to bring global minds together to find the answers to this ethnic and global disparity. The three-year project has just started and we have a lot of work to do.
Professor Riana Bornman is co-principal investigator and clinical leader of the Southern African Prostate Cancer Study (SAPCS), which is investigating the factors, both genetic and non-genetic, driving aggressive prostate cancer in African men. This is being done in partnership with Professor Vanessa Hayes from the University of Sydney in Australia, as SAPCS Scientific Director and University of Pretoria Extraordinary Professor.