Taking the breast cancer drug anastrozole for five years reduced the chances of post-menopausal women at high risk of breast cancer developing the disease by 53% compared with women who took a placebo, according to a study published in the Lancet* today.
The results of the IBIS II trial, funded by Cancer Research UK and led by Queen Mary University of London, could offer a new option for preventing breast cancer in high risk post-menopausal women which is more effective than tamoxifen and has fewer 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.
Professor Jack Cuzick, lead researcher and head of Queen Mary University of London's Centre for Cancer Prevention, said: "This research is 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.
"Unpleasant side effects such as acute aches and pains have often been associated with oestrogen depriving drugs. However, in this study, the reported side effects were only slightly higher than in the placebo arm. This means most symptoms were not drug related, and the concern about side effects for this type of drug may have been overstated in the past.
"Our priority now is ensuring that as many women as possible can benefit from these new findings. Prevention is an important tool in the fight against breast cancer and we strongly urge the National Institute for Health and Care Excellence (NICE) to consider adding anastrozole to their recommended drugs for women who are predisposed to developing breast cancer. By including this drug in their clinical guidelines, more women will benefit from this important advancement in preventive medicine."
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.
Women were judged to be at high risk of breast cancer if they fulfilled one of the following criteria: having two or more blood relatives with breast cancer, having a mother or sister who developed breast cancer before the age of 50, and having a mother or sister who had breast cancer in both breasts, or having certain high risk types of benign breast disease.
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."
Dr Harpal Kumar, Cancer Research UK's chief executive, said: "Cancer Research UK has been funding the IBIS II trial for more than 10 years. 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. 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."
For media enquiries contact Simon Shears in the Cancer Research UK press office on 020 3469 8054 or, out of hours, on 07050 264 059.
Charli Scouller, PR Manager for Queen Mary University of London (School of Medicine and Dentistry) on 020 7882 7943 or 07709 825 741, firstname.lastname@example.org
About Queen Mary University of London
Queen Mary University of London is one of the UK's leading research-focused higher education institutions with 17,000 undergraduate and postgraduate students.
A member of the Russell Group, QM is amongst the largest of the colleges of the University of London. QM's 4,000 staff deliver world-class degrees and research across 21 academic departments and institutes, within three Faculties: Science and Engineering; Humanities and Social Sciences; and the School of Medicine and Dentistry.
Queen Mary is ranked 11th in the UK according to the Guardian analysis of the 2008 Research Assessment Exercise, and has been described as 'the biggest star among the research-intensive institutions' by the Times Higher Education. In 2012, a Queen Mary study was awarded Research Project of the Year at the Times Higher Education Awards. The university has been nominated again in 2013.
In 2014, Queen Mary was positioned 35th among 130 UK universities in the Complete University Guide and 36th according to the Guardian University Guide. The 2013-4 QS World Rankings placed us 115th of 700 universities worldwide and 19th in the UK, while the 2013 Shanghai Jiao Tong Academic Rankings of World Universities placed us in the top 30 in the UK and in the top 201-300 bracket worldwide.
QM has a strong international reputation, with around 20 per cent of students coming from over 150 countries. The university has an annual turnover of £350m, research income worth £100m, and generates employment and output worth £700m to the UK economy each year.
QM is unique amongst London's universities in being able to offer a completely integrated residential campus, with a 2,000-bed award-winning Student Village on its Mile End campus.
About Cancer Research UK
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