Trial Information

INTERNATIONAL BREAST CANCER INTERVENTION STUDY: A MULTICENTRE TRIAL OF TAMOXIFEN TO PREVENT BREAST CANCER

OBJECTIVES: I. Evaluate whether tamoxifen taken daily for 5 years reduces the incidence of
and mortality from breast cancer in high-risk women. II. Assess the risks and benefits of
this intervention.

OUTLINE: This is a randomized, double-blind, placebo-controlled study. Participants are
stratified by participating institution. Participants are randomly assigned to receive
either oral tamoxifen or oral placebo every day for 5 years in the absence of breast cancer
development or pregnancy. Participants are followed every 6 months for 5 years; then
annually for 5 years. Peer Reviewed and Funded or Endorsed by Cancer Research UK

PROJECTED ACCRUAL: 7,000 women will be entered at a rate of 200-500 women/institution/5
years.