Exemestane or Anastrozole in Treating Postmenopausal Women Who Have Undergone Surgery for Primary Breast Cancer
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Study type: Interventional
Phase: Phase 3

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.
    

Intervention name(s): anastrozole; exemestane
Intervention type(s): Drug; Drug
Intervention description(s): Given orally; Given orally
Intervention MeSH terms: Anastrozole; Exemestane
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: stage IIIA breast cancer; stage I breast cancer; stage II breast cancer