Breast cancer risk from using HRT is ‘twice what was thought’

Study prompts medicines regulator to advise all women using HRT to remain vigilant

A woman applies an HRT patch
The study shows one in 50 women taking the most common HRT for five years will get breast cancer. Photograph: Phanie/Alamy

The risk of breast cancer from using hormone replacement therapy is double what was previously thought, according to a major piece of research, which confirms that HRT is a direct cause of the cancer.

The findings of the definitive study will cause concern among the 1 million women in the UK and millions more around the world who are using HRT. It finds that the longer women take it, the greater their risk, with the possibility that just one year is risk-free. It also finds that the risk does not go away as soon as women stop taking it, as had been previously assumed.

The UK’s drug licensing body suggested women who have used HRT in the past or use it now should be vigilant for signs of breast cancer in the light of the findings, while the Royal College of GPs urged them not to panic but to consult their doctor if they are concerned.