A drug used in medical abortions could help prevent breast cancer in high-risk women, according to an international group of doctors and scientists. However, they claim that stigma surrounding mifepristone is deterring pharmaceutical companies from researching its potential as a preventive treatment.
In an opinion piece published in The Lancet Obstetrics, Gynaecology and Women's Health, eight reproductive health experts argue that the drug's association with abortion is hindering studies. They note that three previous trials—conducted in 2008, 2022 and 2024—found mifepristone could slow the growth of cancerous cells by blocking the hormone progesterone.
Breast cancer is the most common female cancer worldwide, killing an estimated 670,000 women annually. If proven effective, mifepristone could offer a non-surgical option for women at high risk, such as those with BRCA gene variants, who currently face mastectomy or low-efficacy drugs.
UK cancer charities have endorsed the call for more research. Dr Simon Vincent of Breast Cancer Now said: 'More risk-reducing treatment options for women with a high risk of developing breast cancer... are desperately needed.' Dr Marianne Baker of Cancer Research UK added: 'Early studies showed that mifepristone slowed down cell growth in breast tissue, so it might be useful in delaying or preventing cancer.'
Lead author Prof Kristina Gemzell Danielsson of the Karolinska Institute in Stockholm said: 'Stigma around mifepristone used for abortion is describing part of why mifepristone is not more extensively researched... Taken together, our data support the use of mifepristone for prevention of poor prognosis breast cancer.'
