anastrozole could HALVE risk of breast cancer in women with high risk Taking anastrozole for five years cuts the risk of the disease by 53 per cent Compared to tamoxifen, it is more effective, has fewer side effects and is just as cheap - it costs Â£120 for a complete preventative course The drug tamoxifen already cuts the risk of breast cancer by a third, but has menopause-like side effects Thousands of women at high risk of breast cancer could benefit from a daily pill that halves their risk of developing the disease, according to scientists. Taking the drug anastrozole for five years cuts the risk by 53 per cent compared with a dummy pill, a trial found. The results could transform the options for post-menopausal women with a family history of breast cancer or other risk factors. A breast cancer prevention drug offers a new option to women at high risk of the disease. It means that, unlike Angelina Jolie and Sharon Osbourne, they might not feel they need to have their breasts removed Earlier this year NHS guidelines recommended for the first time the drugs tamoxifen and raloxifene as a preventative measure for such women. But the latest research shows anastrozole is more effective, has fewer side effects and is just as cheap â€" costing around Â£120 in total for a preventive course of pills. Tamoxifen cuts the risk by a third, with protection lasting up to 20 years, but it has menopause-like side-effects such as hot flushes and more serious, rarer problems including an increased risk of cancer of the womb lining. However, the NHS guidance meant almost half a million healthy women at higher risk had a less drastic alternative to having their breasts removed, a step taken by celebrities in this group such as Angelina Jolie. The latest study looked at almost 4,000 postmenopausal women at high risk of breast cancer with an average age of 59. Half were given 1mg of anastrozole daily and half had a placebo. In the five years of follow-up, 40 women in the anastrozole group developed breast cancer compared with 85 women in the placebo group â€" a cut of 53 per cent. The IBIS II trial, funded by the Cancer Research UK charity, was published in The Lancet medical journal. Taking the drug anastrozole for five years cuts the risk by 53 per cent compared with women taking a dummy pill. Image shows a molecular model of anastrozole Professor Jack Cuzick, lead researcher and head of Queen Mary University of Londonâ€™s Centre for Cancer Prevention, said the National Institute for Health and Care Excellence (Nice) should urgently re-visit its guidance. â€˜We now know anastrozole should be the drug of choice,â€™ he said. Compared to tamoxifen, anastrozole is more effective, has fewer side effects and is just as cheap - costing around Â£120 in total for a preventive course of pills Research shows some women taking tamoxifen long-term are deterred by the side effects. Many breast tumours are fuelled by the hormone oestrogen. Anastrozole, brand name Arimidex, works by preventing the body making oestrogen and, like tamoxifen, has been used for years to prevent recurrence after surgery. Women were deemed at high risk if they met criteria including having two or more blood relatives with breast cancer or having a mother or sister who developed it before the age of 50. Experts fear there may be a significant delay in Nice reviewing the guidelines because it has only just produced them. Its guideline development group also looked at drugs like anastrozole, but there was not enough evidence at the time to support them. Professor Tony Howell, of Genesis Breast Cancer Prevention and one of the trial investigators, said: â€˜I saw over 200 women in Manchester after they completed five years on the study and found it difficult to tell whether they were on the active drug or placebo. â€˜This provides us with another preventative option, which has the potential to save and prolong the lives of thousands of women.â€™ Professor Mark Baker, director of the Centre for Clinical Practice at Nice, said: â€˜We will certainly consider this research â€" along with all other available evidence â€" when the Nice guideline on familial breast cancer is next updated.â€™ Anastrozole works by preventing the body from making oestrogen and, like tamoxifen, has for many years been used to prevent recurrence after surgery Dr Caitlin Palframan, Head of Policy at Breakthrough Breast Cancer, said: â€˜The challenge will be ensuring drugs like these are actually offered on the NHS, as many eligible women still don't have access to the risk reducing treatments already recommended in national guidelines. â€˜We're working closely with the NHS to ensure important drugs are made available to women when it's appropriate, with the support to help them make an informed choice about their options.â€™ Trial investigator Winthrop Professor Christobel Saunders, from The University of Western Australiaâ€™s School of Surgery, said: â€˜The findings from this research may provide a new approach to prevent breast cancer, not only for women today, but also for their daughters and granddaughters in the future.â€™ Kate Law, director of clinical research at Cancer Research UK, said â€˜This landmark study shows that anastrozole could be valuable in helping to prevent breast cancer in women at higher than average risk of disease. We now need accurate tests that will predict which women will most benefit from anastrozole and those who will have the fewest side-effects.â€™ Anastrozole was originally developed by British company Zeneca Pharmaceuticals, now AstraZeneca, and goes under the brand name Arimidex.