'Remarkable' breast cancer drug could save lives of thousands of women This provides us with another preventative treatment option, which has the potential to save and prolong the lives of thousands of women. Prof Howell said the drug brought the science community: "one step closer to creating a future without breast cancer." Charities described the findings as a 'landmark' breakthrough. Earlier this year the National Institute for Health and Care Excellence (NICE) approved tamoxifen and raloxifene for women over 30 who were at high risk of breast cancer. But the study, led by Queen Mary University and Cancer Research UK proved that anastrozole is more effective and does not have side effects such as acute aches and pains. Lead researcher Professor Jack Cuzick, said the results were an "exciting development" in breast cancer prevention. We now know anastrozole should be the drug of choice when it comes to reducing the risk of breast cancer in postmenopausal women with a family history or other risk factors for the disease. This class of drugs is more effective than previous drugs such as tamoxifen and crucially, it has fewer side-effects. Prof Cuzick called NICE to consider adding anastrozole to their recommended drugs for women who are predisposed to developing breast cancer. Anastrozole, which belongs to a class of drugs called aromatase inhibitors, blocks production of oestrogen. It has been used for years to treat post-menopausal women with hormone-sensitive breast cancer. Around 10,000 post-menopausal women die of breast cancer in Britain each year and around 20 per cent of these are at high risk. If the death rate of the high risk women was cut in half, a thousand women a year could be saved. And If the results were replicated across all 400,000 to 800,000 women in Britain at higher risk of breast cancer around 3,200 deaths would be avoided ever year, Professor Cusick calculates. Kate Law, director of clinical research at Cancer Research UK, said: "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. The study looked at almost 4,000 postmenopausal women at high risk of breast cancer with half being given 1mg of anastrozole daily and half given a placebo. In the five years of follow up 40 women in the anastrozole group developed breast cancer compared to 85 women placebo group. Women were defined as "high-risk" if they had two or more blood relatives with breast cancer, a mother or sister who developed the disease before the age of 50, a mother or sister who developed tumours in both breasts, or certain types of non-malignant breast disease. Many breast cancers are fuelled by the hormone oestrogen. Anastrozole works by preventing the body from making oestrogen and has for many years been used to treat postmenopausal women with oestrogen receptor positive breast cancer. Dr Harpal Kumar, Cancer Research UK's chief executive, said: "We're delighted that the results will now offer women at high risk of breast cancer a new option to significantly reduce their chance of developing the disease," he said. By supporting large trials such as this, which take a long time to complete, we can make discoveries that will help us to save many more lives in the future. Professor Mark Baker, director of the Centre for Clinical Practice at Nice, said the body would be considering the research. The findings are published in The Lancet.