Conditions: Breast Cancer
Keywords: breast cancer in situ ductal breast carcinoma in situ
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 3104
Healthy volunteers: no

Brief summary:
RATIONALE: Estrogen can stimulate the growth of breast cancer cells. Tamoxifen may fight breast cancer by blocking the use of estrogen. Anastrozole may fight breast cancer by decreasing estrogen production. It is not yet known whether anastrozole is more effective than tamoxifen in preventing the recurrence of breast cancer.

PURPOSE: This randomized phase III trial is studying anastrozole to see how well it works compared to tamoxifen in preventing the recurrence of breast cancer in postmenopausal women with ductal carcinoma in situ who are undergoing lumpectomy and radiation therapy.

Detailed description:
OBJECTIVES:

* Compare the value of anastrozole vs tamoxifen, in terms of preventing recurrence (i.e., local, regional, and distant recurrences and contralateral breast cancer), after lumpectomy and radiotherapy in postmenopausal women with ductal carcinoma in situ (DCIS).
* Compare subsequent disease occurrence, in terms of invasive breast cancer (local, regional, distant, or contralateral), ipsilateral and contralateral breast cancer (invasive and DCIS), and non-breast second primary malignancies, in patients treated with these drugs.
* Compare quality of life and symptoms of patients treated with these drugs.\*
* Compare quality-adjusted survival time of patients treated with these drugs.\*
* Compare the occurrence of osteoporotic fractures in patients treated with these drugs.
* Compare disease-free and overall survival of patients treated with these drugs. NOTE: \*The quality of life study closed to accrual as of 12/28/04.

OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to age (under 60 vs 60 and over). Patients are randomized to 1 of 2 treatment arms (arm I and arm II closed to accrual as of 6/15/06).

* Arm I (closed to accrual as of 6/15/06): Patients receive oral tamoxifen and oral placebo once daily for 5 years.
* Arm II (closed to accrual as of 6/15/06): Patients receive oral anastrozole and oral placebo once daily for 5 years.

Beginning within 8 weeks of randomization, all patients also undergo whole breast radiotherapy, unless the patient is enrolled in protocol NSABP-B-39 and randomized to the partial breast irradiation group.

Patients are followed every 6 months for 5 years, and then annually thereafter.

For patients enrolled in the quality of life study, quality of life is assessed at baseline and then every 6 months for 6 years.\*

NOTE: \*The quality of life study closed to accrual as of 12/28/04.

PROJECTED ACCRUAL: A total of 3,000 patients (1,500 per treatment arm) will be accrued for this study within 5 years (arm I and arm II closed to accrual as of 6/15/06).

Arms:
arm 1: tamoxifen 20 mg/day and an anastrozole look-alike placebo for 5 years arm 2: anastrozole, 1 mg/day and an tamoxifen look-alike placebo for 5 years

Interventions: intervention 1: anastrozole intervention 2: tamoxifen citrate intervention 3: Radiation Therapy
Intervention descriptions: intervention 1: 1 mg/day and placebo for 5 years intervention 2: 20 mg/day and placebo for 5 years intervention 3: Adjuvant radiation therapy

Protocol document: