Name of the Trial
Phase III Randomized Study of Ovarian Function Suppression in Combination with Tamoxifen versus Ovarian Function Suppression in Combination with Exemestane versus Tamoxifen Alone in Premenopausal Women with Endocrine-Responsive Breast Cancer (IBCSG-24-02). See the protocol summary at http://cancer.gov/clinicaltrials/IBCSG-24-02.

Study Chairs
Dr. Gini Fleming, North American Breast Intergroup; Dr. Prudence Francis, Breast International Group

Why Is This Trial Important?
Many women with breast cancer have tumors that grow in response to the female hormone estrogen (endocrine-responsive tumors). The drug tamoxifen has been used to treat endocrine-responsive breast cancer in both premenopausal and postmenopausal women.

Recently, a new class of drugs called aromatase inhibitors was shown to improve disease-free survival in postmenopausal women with endocrine-responsive cancers. However, aromatase inhibitors are not effective in premenopausal women because their ovaries are still producing estrogen.

In this trial, researchers will study three groups of premenopausal women with endocrine-responsive breast cancer. Menopause will be induced in two of the groups; one group will be treated with tamoxifen, the other with the aromatase inhibitor exemestane. Menopause will not be induced in the third group, which will be treated with tamoxifen. The researchers hope to determine which treatment approach is most effective in preventing breast cancer recurrence in premenopausal women.

"Young women with endocrine-responsive breast cancer have a high risk for recurrence if not treated with antihormone therapy," said Dr. Fleming. "We are trying to explore ways to improve that therapy for these patients."

Who Can Join This Trial?
Researchers seek to enroll 3,000 premenopausal women diagnosed with breast cancer who have had their tumors surgically removed. See the list of eligibility criteria at http://www.cancer.gov/clinicaltrials/IBCSG-24-02.

Where Is This Trial Taking Place?
Study sites in the United States are recruiting patients for this trial. See the list of sites at http://www.cancer.gov/clinicaltrials/IBCSG-24-02.

Contact Information
See the list of study contacts at http://www.cancer.gov/clinicaltrials/IBCSG-24-02 or call NCI's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237). The toll-free call is confidential.