Pilot Study of the Impact of a Physical Activity Intervention on Proliferation and Immune Markers in Benign Breast Tissue in Women with High Mammographic Breast Density

This research study is evaluating the effect of exercise on markers in breast tissue and
blood of premenopausal women who have been found to have dense breast tissue on mammogram.

Inclusion Criteria:

- Written informed consent prior to any study-related procedures

- Premenopausal women, defined as:

- having regular menstrual cycles

- age ≤ 50 years with an intact IUD

- history of hysterectomy without oophorectomy

- Heterogeneously dense or very dense (BIRADS 3 or 4) breast tissue on mammogram within
the last 3 years

- Physically inactive; engaging in <90 minutes of moderate or vigorous intensity PA per
week

- No prior history of breast cancer

- At least 18 years old

- Physically able to exercise

- English speaking and able to read English

Exclusion Criteria:

- Self-reported inability to walk 2 blocks (at any pace)

- Prior history of breast cancer; prior DCIS is allowable as long as participant is not
taking endocrine therapy and has at least 1 breast that has not been irradiated.

- On oral contraceptives; Mirena IUD is acceptable

- Cardiovascular, respiratory or musculoskeletal disease or joint problems that preclude
moderate physical activity. Examples would include unstable angina, recent myocardial
infarction, oxygen-dependent pulmonary disease, and osteoarthritis requiring imminent
joint replacement. Moderate arthritis that does not preclude physical activity is not
a reason for ineligibility.

- Psychiatric disorders or conditions that would preclude participation in the study
intervention (e.g. untreated major depression or psychosis, substance abuse, severe
personality disorder)