Cancer specialist from the Los Angeles Biomedical Research Institute Rowan Chlebowski said that Prempro, a combination of the hormones estrogen and progestin, does relieve hot flashes but raises the risk of the two biggest cancer killers in women.

It was also added by him that about 15 to 20 per cent of postmenopausal women in the USA use Prempro.

Women's risk of breast cancer and that their cancers were more likely to have spread to their lymph nodes were increased by Prempro as compared to a placebo, Chlebowski and his coauthors reported.

Breast cancer was more likely to happen in women who took hormones.

Their findings put the safety of hormone therapy under doubt. It was also stated that Prempro was responsible for increasing the number of lung cancer deaths but it was also stated that there was no increase in the number of lung cancer cases by the drug.

A government-sponsored study known as the Women's Health Initiative conclude the above findings.

About 16,000 women who were aged between 50 to 79 were given a placebo or Prempro but they were asked to stop it as it was found that Prempro was increasing the risk of breast cancer, stroke and heart attack. For about 5.5 years the pill was being taken by the participants.

Once the participants stopped taking the drug, within two years their breast cancer risk appeared to drop markedly.