Cognition in the Study of Tamoxifen and Raloxifene

Recent reports indicate that hormone therapy (HT) may have a protective effect on the aging
brain. Although previous studies have examined the effects of HT on age-related cognitive
changes, there is little information on the effect of a new class of estrogenic agents,
selective estrogen receptor modulators (SERMs), on cognitive aging. The two most commonly
prescribed SERMs are tamoxifen, for treatment and prevention of breast cancer, and
raloxifene, for maintaining bone density. In the face of potential widespread use of SERMs in
healthy women, information on the effects of these agents on memory and other cognitive
functions is essential.

The principal goals of Co-STAR are to compare the effects of tamoxifen and raloxifene

- on age-associated declines in measures of verbal and nonverbal memory in women over age
65

- other cognitive abilities and mood

- with those resulting from more common forms of HT, specifically ET (conjugated equine
estrogen) and ET plus progesterone

Co-STAR results will be compared to results from the Women's Health Initiative Study of
Cognitive Aging (WHISCA), a study involving 6-year longitudinal assessment of cognitive
outcomes in 2969 women randomly assigned to receive active treatment (Premarin or Premarin
plus medroxyprogesterone acetate) or placebo. A comparison of the Co-STAR treatment groups
with the group of WHISCA participants receiving placebo will provide insights into the
effects of SERMs relative to no treatment. A comparison of the Co-STAR treatment groups with
WHISCA treatment groups receiving ET or ET plus progesterone will provide insights into the
effects of SERMs relative to common HT treatments.

Co-STAR participants will be recruited from The National Cancer Institute's (NCI) Study of
Tamoxifen and Raloxifene (STAR) NCT00003906, a multi-center, 5-year, randomized clinical
trial among 22,000 women at increased risk for breast cancer, to compare the effects of
tamoxifen and raloxifene on risk for breast cancer.

Inclusion Criteria:

- Women enrolled in STAR trial at a site participating in Co-STAR

- 65 years of age or older

- Have been randomized into STAR but have not started taking the study drug OR enrolled
in STAR for a minimum of one year

- Have not been diagnosed with dementia

- Have signed a separate consent document for the Co-STAR Study

- Previous diagnoses of chronic neurologic disease (Parkinson's disease, stroke,
epilepsy, multiple sclerosis), history of head injury, depression, alcohol addiction,
drug addiction, and other neurologic or psychiatric conditions will be recorded but
will not serve as exclusion factors for this study

Exclusion Criteria:

- Not enrolled in the STAR Trial

- Younger than 65 years of age

- Diagnosed with dementia