International Breast Cancer Intervention Study II (IBIS-II) (DCIS)
- 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.
- 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
Patients are followed annually for 5 years and a further 5 years 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.
Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Treatment
Development of histologically confirmed breast cancer, both invasive and non-invasive with median follow-up at 5 years
Jack Cuzick, PhD
Cancer Prevention Trials Unit, Queen Mary University of London
United Kingdom: Research Ethics Committee