A Study to Investigate the Effects of Tibolone (Livial®) on Breast Tissue in Postmenopausal Women With Breast Cancer (Study 32971)(P06469)

A Exploratory, Double-blind, Randomized, Placebo-controlled Trial to Investigate the Tissue Specific Effects of 2.5 mg Tibolone on Breast Cancer in Postmenopausal Women, in Particular on Breast Tissue Proliferation.

The primary purpose of this study is to compare changes in the expression of the proliferation marker Ki-67 in malignant breast tissue after treatment with tibolone or placebo in postmenopausal women who need to undergo surgery for primary breast cancer

Inclusion Criteria:

• postmenopausal women of any age
• requiring surgery for early invasive primary breast cancer (clinically stage I or II; T1-T3; N0-1; M0), with estrogen receptor-positive tumor(s)
• body mass index between 18 and 2 kg/m2, inclusive
• must be willing to give voluntary written informed consent.

Exclusion Criteria:

• healthy subjects