Conditions: Breast Cancer
Keywords: stage IIIA breast cancer stage I breast cancer stage II breast cancer
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 7576
Healthy volunteers: no

Brief summary:
RATIONALE: Estrogen can stimulate the growth of breast cancer cells. Hormone therapy, using exemestane or anastrozole, may fight breast cancer by reducing the production of estrogen. It is not yet known whether exemestane is more effective than anastrozole in preventing the recurrence of breast cancer.

PURPOSE: This randomized phase III trial is studying exemestane to see how well it works compared to anastrozole in preventing cancer recurrence in postmenopausal women who have undergone surgery for primary breast cancer.

Detailed description:
OBJECTIVES:

Primary

* Compare the event-free survival of postmenopausal women with receptor-positive primary breast cancer when treated with exemestane vs anastrozole.

Secondary

* Compare the overall survival of patients treated with these regimens.
* Compare the time to distant recurrence in patients treated with these regimens.
* Compare the incidence of new primary contralateral breast cancer in patients treated with these regimens.
* Compare the incidence of all clinical fractures, specifically hip and vertebral fractures, in patients treated with these regimens.
* Compare cardiovascular morbidity and mortality (i.e., significant coronary heart disease, which includes myocardial infarctions and angina requiring percutaneous transluminal coronary angioplasty or coronary artery bypass graft, fatal and nonfatal strokes, and all vascular deaths) in patients treated with these regimens.
* Correlate therapy induced changes in breast density with plasma hormones and growth factors, drug levels of exemestane and anastrozole, genetic variation and breast cancer recurrence or contralateral events in patients treated with these regimens.
* Compare the toxic effects of these regimens in these patients.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to lymph node status at diagnosis (negative vs positive vs unknown), prior adjuvant chemotherapy (yes vs no), and herceptin use (yes vs no). Patients are randomized to 1 of 2 treatment arms.

* Arm I: Patients receive oral exemestane (25 mg) once daily for 5 years.
* Arm II: Patients receive oral anastrozole (1 mg) once daily for 5 years. In both arms, treatment continues in the absence of disease progression or unacceptable toxicity.

Patients are followed every 6 months during the first year of study participation and annually thereafter.

PROJECTED ACCRUAL: A total of 6,840 patients will be accrued for this study.

Arms:
arm 1: Patients receive oral exemestane (25 mg) once daily for 5 years. arm 2: Patients receive oral anastrozole (1 mg) once daily for 5 years.

Interventions: intervention 1: anastrozole intervention 2: exemestane
Intervention descriptions: intervention 1: Given orally intervention 2: Given orally

Protocol document: