The findings, published today 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 National Institute for Health and Care Research 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 BRCA genes), 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."
Fiona Miller Smith, Chief Executive of Barts Charity, said: "Equity in healthcare is an important need for East London. Inequalities in health outcomes in certain ethnic populations, such as people from African or South Asian ancestry, are often made worse by underrepresentation in research data and studies. That's why we fund so many projects that help to improve health outcomes for people from different backgrounds – including Professor Claude Chelala and her team's study published today. The findings point to the need for increasing data collection of underrepresented groups in research studies – to ensure medical advances benefit everyone in our community."
Dr Kotryna Temcinaite, Head of Research Communications and Engagement at Breast Cancer Now, said: "We know that inequalities are present at every stage of the breast cancer experience for women from ethnic minority communities, from barriers to seeking help, to survival rates.
"This research, which was made possible with data from the Breast Cancer Now Biobank*, will help us find ways to improve breast cancer treatment and outcomes for women from ethnic minority communities.
"Breast Cancer Now also funds further research to address physical, mental and emotional wellbeing and inequalities experienced in breast cancer, so that everyone receives the best possible breast cancer care regardless of their ethnicity.
"Anyone affected by breast cancer can speak to Breast Cancer Now's expert nurses by calling our free, confidential helpline on 0808 800 6000 for information and support."
Balwinder's story – "With cancer, there's no one-size-fits-all approach"
Balwinder Nanray lives in Essex with her husband and son. She now volunteers as a patient advocate, using her voice to help ensure cancer patients in underrepresented communities are heard. In 2015, she was diagnosed with breast cancer following a routine mammogram organised through her workplace.
"I had no symptoms and no lumps. I was a senior leader in financial services, but breast cancer had other ideas. I underwent surgery, chemotherapy, and radiotherapy, and I am currently on hormone therapy to help reduce the risk of the cancer returning. This year marks nearly 10 years since my diagnosis, and I'm very grateful for that.
"My medical team has been amazing, but at times it was difficult to build a trusting relationship with some of my physicians. There were moments when I felt like I was being treated as a number rather than a person.
"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.
"I now participate as a patient advocate for several cancer charities, including Breast Cancer Now. I'm passionate about using my voice to help others from underrepresented communities be heard. This includes not only people from ethnic minority backgrounds, but also groups such as people with disabilities, those experiencing homelessness, and refugees. I want to help break down the stigma and taboos that still surround cancer. If I can make a difference in just one person's life would be an incredible achievement."
