Breast cancer drug halves disease risk in post-menopausal women

London –  A new study has shown that taking the breast cancer drug anastrozole for five years reduces the chances of developing the disease in high risk post-menopausal women by 53 percent compared with women who took a placebo.

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 the study suggested that 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,” Cuzick said.

“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 study was published in journal Lancet.