Français | Español What can I expect if I join ExCel? Why is ExCel a placebo-controlled clinical trial? Learn more about the ExCel research study Breast cancer is the most common form of cancer in women. In 2004, more than 1.2 million people worldwide were diagnosed with this disease. Breast cancer can occur in adults at any age. Recent research in breast cancer has helped thousands of women beat their disease and researchers are dedicated to finding even better treatment options. Recent efforts are also now focusing on new medications that may reduce the occurrence of breast cancer in women who are at an increased risk for developing this disease. The ExCel research study is a phase III breast cancer prevention clinical trial. It is a new and important international clinical trial designed to determine whether a special type of medication can prevent breast cancer in healthy postmenopausal women who are at an increased risk for developing breast cancer. The ExCel research study is coordinated by the National Cancer Institute of Canada Clinical Trials Group in cooperation with Pfizer Inc., well women and cancer centers in Canada, the United States and Spain. More than 4,500 women will take part in the ExCel research study. What is the design of the ExCel study? Women eligible for the study will be randomly assigned to 1 of 2 treatment groups and all women will take one pill per day for five years. If you are in Group A you will get 1 exemestane tablet. If you are in Group B you will get 1 placebo, which is an inactive substance that does not have any of the medicine being studied in the trial. What is the medication used in this trial and why? After menopause, when the ovaries stop making estrogen, the body continues to make estrogen from skin, muscle and fat. Even though it is only present at low levels, it continues to be very important in the development of breast cancer. Exemestane is one member of a class of drugs called aromatase inhibitors. Aromatase inhibitors limit the body’s ability to produce estrogen. Estrogen plays a key role in the development and growth of most types of breast cancer and inhibition of estrogen may prevent breast cancer in many women. Exemestane is Health Canada and FDA approved and marketed as AROMASIN™. It is currently used for the treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy. How long will the study last? The study will enroll subjects for 3 years and the results should be available 2 to 3 years after that.