Women currently using hormone replacement therapy increases have an increased risk of breast cancer, no matter how long they've taken the drug.

A large scale American study by Harvard Medical School of l2l,700 women that the risk of breast cancer was "significantly" elevated (l.36 times) among current users of HRT, compared to women who had never taken the drug.Among current users, a stronger relationship was observed with increasing age but not with increasing duration of use," said the study.

This counters the claim of the Amarant Trust and the earlier medical view that breast cancer risk only increased after the drug had been taken for l0 years or more.

The study also found no increased risk among women who had taken the drug in the past, but had stopped.

"The lack of a duration effect suggests that oestrogens may act acutely to increase risk and that this effect is reversible within perhaps two years of cessation," said the study.

Although oestrogen replacement therapy has been touted as beneficial because it supposedly lessens the risk of cardiovascular disease or osteoporosis, the study authors conclude that the story is far more complex and that caution needs to be exercised in the use of oestrogens.