The concern is about HRT creating extra risk: about one in 16 women who have never used HRT will still go on to develop breast cancer between the ages of 50-69 years.10

The Lancet paper said that the risk of using combination HRT for five years from the age of 50 “would increase 20-year breast cancer risks at ages 50–69 years from 6.3 per cent to 8.3 per cent, an absolute increase of 2.0 per 100 women (one in every 50 users).”7

For oestrogen plus intermittent progestogen HRT, 20-year risk increases from 6.3 per cent to 7.7 per cent, an absolute increase of 1.4 per 100 women (one in 70 users). And for oestrogen-only HRT, the 20-year risk increases from 6·3 per cent to 6·8 per cent, an absolute increase of 0.5 per 100 women (one in 200 users).

These figures are for women of average weight in western countries. The paper notes that breast cancer risk from oestrogen-only HRT would be greater in leaner women, but in obese women there was little excess risk.

The MHRA advised that women who are current or past users of HRT should remain vigilant for signs of breast cancer, even after stopping HRT.9