Women of African or South Asian genetic ancestry tend to develop breast cancer and die at a younger age than women of European ancestry, according to new research by Queen Mary University of London. The study, which looked at clinical and genetic data from over 7,000 women with breast cancer, also found important genetic differences in these women's cancers that could impact their diagnosis and treatment.
The findings, published today (20 May) in Nature Communications, highlight the underrepresentation of people of non-European genetic ancestry as participants in cancer studies and emphasise an urgent need to break down barriers preventing medical advances from benefiting everyone equally.
Currently, people of European ancestry account for nearly 80% of participants in genetic association studies, despite representing only 16% of the global population. This imbalance means that most of our knowledge about risk, prevention, and treatment is based predominantly on European populations.
Professor Claude Chelala and her team at Queen Mary University of London analysed genetic data and clinical records from over 7,000 women with breast cancer of African, South Asian and European ancestry, using data from four major research initiatives in the UK and US: The Breast Cancer Now Biobank, the 100,000 Genomes Project, the Genes & Health study, and the Cancer Genome Atlas. The research was funded by Breast Cancer Now, Barts Charity and the NIHR Barts Biomedical Research Centre.
Compared with women of European ancestry, those from South Asian backgrounds were diagnosed nearly seven years earlier and died around thirteen years younger, while women of African ancestry were diagnosed around five years earlier and died nearly nine years younger. The researchers suggest that current NHS screening guidelines, which recommend breast screening for all women from age 50, may start too late for women from some backgrounds and should be reviewed based on ancestry.
The study also identified differences in mutation rates in genes linked to breast cancer susceptibility (including the BRCAgenes), which are used in genetic testing and influence treatment decisions. Some women had genetic mutations that could have made their cancer resistant to certain treatments they received, but this was not factored into their clinical management. If this information had been available at diagnosis, it could have been used to inform the choice of different treatments.
"Precision medicine has the power to revolutionise cancer care, but only if it works for everyone," says Professor Chelala, who is Professor of Bioinformatics at Queen Mary's Barts Cancer Institute. "If we fail to address blind spots in research, we risk widening health inequalities rather than reducing them."
"Our study is among the largest of its kind in these populations, but we need even larger cohorts to validate and fully understand the genetic and clinical factors affecting breast cancer across diverse populations. We hope our results will serve to guide further research. Funders and scientists need to work together and rethink how we design cancer research studies and clinical trials to represent a balance of ethnicities and ensure that no group is left behind."
Balwinder Nanray was diagnosed with cancer in 2015 and now volunteers as a patient advocate, using her voice to help ensure cancer patients in underrepresented communities are heard. She says: "With cancer, one size does not fit all, and it's important that we're all treated as individuals. Beyond your cancer diagnosis, you are a person, and I think people can forget that. Co-producing and collaborating with patients in research can lead to more effective and sustainable solutions that better meet patients' needs."
