According to a new study, a type of hormone replacement therapy (HRT) protects women from breast cancer.

The researchers found that oestrogen-only hormone replacement therapy reduces rates of the disease by nearly a quarter. They studied 7,500 women who took oestrogen-only HRT for seven years and found that they were 23% less likely to have developed the disease than others.

According to the study by US study of post-menopausal women called, Women's Health Initiative (WHI), women who received Oestrogen-only HRT and developed the disease, were also 63% less likely to die from the disease. The Oestrogen-only HRT treatment is linked to cancer of the womb and is thus only used to treat women who have undergone a hysterectomy.

The researchers said that women who received oestrogen-only HRT for around seven years continued to have protection against the disease even after they stopped receiveing the treatment.

They also found that women who have higher than normal risk of the disease did not appear to be protected by the treatment. The benefit of oestrogen-only HRT also has to be balanced against an increased risk of blood clots and strokes associated with HRT.

Some claim that the more common form of HRT containing both oestrogen and the hormone results in higher risk of the disease. The claim has created a lot of controversy in the scientific community and it is yet to be substantiated.

The latest study has been published online in The Lancet Oncology journal.