Use of oestrogen-only HRT by women with prior hysterectomy is associated with a lower risk of death from breast cancer, according to long-term follow-up of two landmark trials.

The studies of more than 27,300 participants who had been in the Women’s Health Initiative trials and followed for more than 20 years show divergent results on breast cancer risk. 

Women with no uterus who took conjugated equine oestrogen 0.625mg a day during a seven-year trial had a lower risk of developing breast cancer and a 40% lower risk of dying from it than women on placebo. 

It meant in absolute terms that for every 10,000 patient-years, there would be four fewer breast cancer deaths, the US researchers said.