IBCSG 30-04 / NCIC CTG MA.27

IBCSG 30-04 / NCIC CTG MA.27 is co-ordinated by the National Cancer Institute of Canada, Clinical Trials Group (NCIC CTG). The International Breast Cancer Study Group (IBCSG) is participating in the NCIC CTG MA.27 trial, and the ANZ Breast Cancer Trials Group (ANZ BCTG) contribution is part of the IBCSG collaboration. The trial is conducted in Australia and New Zealand by the ANZ Breast Cancer Trials Group. This study will investigate which of two drugs (exemestane and anastrozole), if either, is better at preventing a recurrence of breast cancer in postmenopausal women with receptor positive, adequately excised, primary breast cancer. IBCSG 30-04 / NCIC CTG MA.27 is an international, multicentre, randomised phase III clinical trial of 5800 postmenopausal women who have had histologically or cytologically confirmed, receptor-positive primary breast cancer. Women will be randomised in a 2-arm design to receive one of the following: a. Exemestane 25mg b. Anastrozole 1mg All treatment will be on a daily basis for 5 years until recurrence or second malignancy is documented.