Women at increased risk of developing breast cancer are needed to participate in a clinical trial which aims to identify a drug to help prevent the disease.

The IBIS-II trial is being run by the Australia New Zealand Breast Cancer Trials Group and Cancer Research UK and focuses on the drugs Anastrozole and Tamoxifen and whether they are beneficial in helping to prevent breast cancer.

Waikato breast surgeon, Associate Professor Ian Campbell, says around 6000 New Zealand, Australian and British women are needed to participate in the study.

“Prevention is better than cure and the IBIS-II study is all about identifying ways of preventing breast cancer, so it’s very exciting from that point of view,” Professor Campbell says.

The IBIS-II clinical trial has two separate arms.  These are:

    * The IBIS-II (Prevention) study

This aims to identify whether the drug Anastrozole is beneficial in helping to prevent breast cancer.  It will compare the use of the Anastrozole versus a placebo in 6000 post menopausal women, aged between 40 and 70, who are at increased risk of developing breast cancer. Those at increased risk are defined as those with a family history of the disease or those who have had certain benign breast diseases. Women who participate in this study will have to take one tablet daily for five years.

    * The IBIS-II (DCIS) study

This arm of the study will compare the use of Anastrozole with Tamoxifen in 4000 post menopausal women, aged 40 to 70, who have had surgery to remove hormone receptor positive Ductal Carcinoma In-Situ (DCIS) in the past six months.  It aims to identify which drug is more effective in preventing further breast cancer from developing. Women who participate in this study will have to take one tablet daily for five years.

The IBIS-II trial follows on from the IBIS-I trial which investigated the use of Tamoxifen as a preventative agent for women with moderate to increased risk of developing breast cancer.

Professor Campbell says results from the IBIS-I study found that the use of Tamoxifen reduced the risk of developing breast cancer in high risk women by 40 per cent.  This reduction in risk lasted for ten years, even though Tamoxifen was only given for five years.

He says comparisons between the use of Tamoxifen and Anastrozole in women with hormone receptor positive breast cancer have already shown that Anastrozole can reduce the risk of new cancers in the previously unaffected breast by 40 per cent compared with Tamoxifen.

Professor Campbell says, “We already know that Tamoxifen reduces the risk of breast cancer in hormone receptor positive women by 40 per cent.  This suggests that Anastrozole may be able to prevent some 70 per cent of hormone receptor positive breast cancers.  The IBIS-II study will help to clarify this and that’s why this is such crucial research.”

Professor Campbell says Anastrozole, like all drugs, does have side-effects and these obviously need to be weighed against any benefits the drug is shown to have.

Click here for more information on the IBISII study.  Alternatively you can phone 0800 888 656 and a local IBIS research nurse will be able to answer your queries.

North Shore, Waikato, Wellington and Christchurch Hospitals are centres for the prevention arm of the trial.  North Shore and Waikato Hospitals are centres also for the DCIS arm of the trial.  Women who participate in the IBIS-II are required to attend these centres for long term follow-up.