Cancer drug availability urged
Experts are calling for a breast cancer drug to be made freely available as a preventative treatment after it was found to halve the likelihood of disease developing in vulnerable women.
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.
Results from a major trial have now shown that taking the drug for five years can reduce the chances of high-risk women going on to develop breast cancer by 53%.
Anastrozole was better at staving off breast cancer than tamoxifen, another hormone-suppressing drug already given as a preventative measure, and had fewer side effects.
The findings prompted experts to urge Nice, the National Institute for health and Clinical Excellence, whose advice shapes NHS policy on new treatments, to recommend anastrozole as a breast cancer prophylactic.
Trial leader Professor Jack Cuzick, 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.
"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."
The Ibis II trial, funded by Cancer Research UK, involved almost 4,000 post-menopausal women at high-risk of breast cancer. Half were given a one milligram dose of anastrozole daily for five years and half an inactive "dummy" placebo.
During the five-year follow-up period, 40 women in the anastrozole group developed breast cancer compared with 85 of those in the 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.
Aromatase inhibitors are designed to block an enzyme involved in the production of oestrogen, which fuels the growth of most breast cancers.
Unlike tamoxifen, that interferes with a tumour's ability to respond to the hormone, it actually cuts off the supply of oestrogen.
Earlier this year Nice issued guidelines which recommended the use of tamoxifen and another drug, raloxifene, as a preventative measure for women susceptible to breast cancer.
The Ibis II findings are published in The Lancet medical journal.
Dr Caitlin Palframan, head of policy at the charity Breakthrough Breast Cancer, said: " This new research suggests that aromatase inhibitors could be a useful alternative for post-menopausal women with a family history of breast cancer, to help prevent the disease.
"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.
"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."
Kate Law, clinical director 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."
Breast cancer is the most commonly diagnosed cancer in the UK, affecting 50,000 women each year and claiming 1,000 lives a month.
Professor Mark Baker, director of the Centre for Clinical Practice at Nice, said: "Nice is committed to ensuring that everyone is able to receive the best care and cost-effective medicines from the NHS and we will certainly consider this research - along with all other available evidence - when the Nice guideline on familial breast cancer is next updated.
"This research is specifically focused on women at high risk of developing breast cancer. It is a relatively small percentage of people in the general population for whom Nice already recommends tamoxifen or raloxifene as treatments to prevent breast cancer.
"Nice recommendations, which were published in June, were developed based on a thorough review of all available evidence which showed that the drugs can be effective in preventing the disease in women with a family history of the disease if the pills are taken for five years."