Drug cuts breast cancer cases by more than 50 per cent in high risk women

Breast Cancer Breakthrough

13 December 2013

World-renowned University of Newcastle researcher, Professor John Forbes AM*, has discovered breast cancer drug anastrozole reduces the risk of breast cancer by 53 per cent in high-risk post-menopausal women.

The international clinical preventions trial, co-chaired by the University of Newcastle's Professor of Surgical Oncology, Professor Forbes, will be published in The Lancet today.

Conducted locally by the Australia and New Zealand Breast Cancer Trials Group (ANZ BCTG), the prevention clinical trial IBIS-II's findings were presented by its international chairman, Professor Jack Cuzick, at the San Antonio Breast Cancer Symposium overnight.

Professor Forbes, Director of Research for the ANZ BCTG and who also works in collaboration with the Hunter Medical Research Institute's (HMRI) Hunter Cancer Research Alliance, said the research was an important step 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," Professor Forbes said.

The results could offer a new option for preventing breast cancer in moderate to high risk postmenopausal women.

"This class of drugs is more effective than current drugs such as tamoxifen and crucially, it has fewer side effects," he said.

"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.

"This very positive result provides women at high risk of breast cancer new options to manage their risk. We know prevention is a key concern for women and we sincerely thank the women of Australia and New Zealand who participated in IBIS-II for their contribution to this new knowledge.

"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."

Many breast cancers are fuelled by the hormone oestrogen. Anastrozole works by preventing the body from making oestrogen and has been used to treat postmenopausal women with oestrogen receptor positive breast cancer.

About the IBIS-II Study:

  • In Australia and New Zealand, 818 participated in the study across 30 institutions.
  • Almost 4,000 postmenopausal women worldwide 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 in the placebo group.
  • IBIS-II received funding in Australia from the National Health and Medical Research Council.

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
  • a mother or sister who developed breast cancer before the age of 50
  • a mother or sister who had breast cancer in both breasts
  • certain high risk types of benign breast disease.

*Professor Forbes is also the Director of Surgical Oncology at the Calvary Mater Newcastle Hospital.

The ANZBCTG is Australia's national organisation dedicated entirely to breast cancer research. The research program involves multicentre clinical trials and collaboration with more than 80 institutions and over 600 researchers throughout Australia and New Zealand.

For further information:

Contact: Sheena Martin
Contact Phone: +61 2 4921 8714
Contact Email: media@newcastle.edu.au