Prof Rob Jones said: "Patients who received the hormone therapy with a placebo had an overall survival of around 20 months and those who received the capivasertib with the hormone therapy had an extra 39 months.

"It really is a doubling of survival time so that really is significant. It's not just a statistic - it's a real life impact for people to spend extra time with their relatives, with their friends."

Dr Nicola Williams, national director of support and delivery at Health and Care Research Wales, said: "A breast cancer diagnosis can be devastating and one in seven women will be diagnosed with the disease in their lifetime.

"This diagnosis is even more painful if you're told your cancer is incurable.

"Thanks to the trial and the licensing of capivasertib, when used alongside a standard hormonal therapy, patients like Gwen now have the potential to receive a very significant extension in their lifespan and improved quality of life."