Conditions: Breast Cancer
Keywords: ductal breast carcinoma in situ breast cancer in situ
Allocation: RANDOMIZED | Intervention model: SINGLE_GROUP
Enrollment: 2980
Healthy volunteers: no

Brief summary:
RATIONALE: Estrogen can stimulate the growth of breast cancer cells. Hormone therapy using either tamoxifen or anastrozole may fight breast cancer by blocking the use of estrogen. It is not yet known whether tamoxifen is more effective than anastrozole in preventing breast cancer after surgery for ductal carcinoma in situ.

PURPOSE: This randomized phase III trial is studying how well adjuvant tamoxifen works compared to anastrozole in treating postmenopausal women who have undergone surgery to remove ductal carcinoma in situ.

Detailed description:
OBJECTIVES:

Primary

* Compare the efficacy of adjuvant tamoxifen vs anastrozole, in terms of local control and prevention of contralateral disease, in postmenopausal women with locally excised ductal carcinoma in situ.
* Compare side effect profiles of these drugs in these patients.

Secondary

* Compare the efficacy of these drugs, according to the receptor status of the primary or recurrent cancer in these patients.
* Compare the rate of breast cancer recurrence and growth of new contralateral tumors after cessation of treatment with these drugs in these patients.
* Compare breast cancer mortality in patients treated with these drugs.
* Compare the effect of these drugs on other cancers, cardiovascular disease, fracture rates, and non-breast cancer deaths in these patients.
* Compare the tolerability and acceptability of side effects experienced by patients treated with these drugs.

OUTLINE: This is a randomized, double-blind, multicentre study. Patients are stratified according to participating centre. Patients are randomized to 1 of 2 treatment arms.

* Arm I: Patients receive oral tamoxifen and oral placebo once daily.
* Arm II: Patients receive oral anastrozole and oral placebo once daily. In both arms, treatment continues for 5 years in the absence of disease recurrence or unacceptable toxicity.

Patients are followed annually for 5 years and a further 5 years (minimum) off treatment.

Peer Reviewed and Funded by Cancer Research UK. Sponsored by Queen Mary University of London

ACTUAL ACCRUAL: A total of 2,980 patients were accrued for this study over 9 years.

Arms:
arm 1: None arm 2: None

Interventions: intervention 1: tamoxifen citrate intervention 2: Anastrozole
Intervention descriptions: intervention 1: Tamoxifen 20mg + Anastrozole placebo intervention 2: Anastrozole 1mg + Tamoxifen placebo

Protocol document: