Dr Kotryna Temcinaite, head of research communications at Breast Cancer Now said:
“This largescale study offers useful insights for women aged under 55 on how HRT (hormone replacement therapy) may influence their chances of developing breast cancer before the menopause.
“It found that oestrogen-only therapy was linked to a lower risk, while combined oestrogen and progesterone therapy was associated with a small increase in risk of developing breast cancer in some women – particularly when used for more than two years or in women who hadn’t undergone surgery to remove their uterus or both ovaries.
“These results are largely in line with what we already know about taking HRT for menopausal symptoms and its effects on breast cancer risk – for most people, the risk of developing breast cancer because of taking HRT is small and is outweighed by the benefits.
“The risk is higher the longer you take it, and the risk is higher with combined HRT compared to oestrogen-only HRT.
“Taking HRT is a very personal decision, and as such it’s vital that everyone has the information they need on the benefits and risks, discusses them with their GP or specialist team and is supported to make the choice that’s right for them.
“We’d encourage anyone with questions about HRT and their breast cancer risk to speak to their GP or to our expert nurses by calling our free, confidential Helpline on 0808 800 6000.”