Vitamin D and Breast Cancer Biomarkers in Female Patients

• Premenopausal women 55 years of age or younger with regular menstrual cycles (at least four cycles in the last six months). Women with fewer than 4 menses in the last 6 months or who have had a hysterectomy with ovaries intact will be considered premenopausal if FSH level < 20.
• Women with breast density ≥ 25% (scattered fibroglandular densities or greater) are eligible.
• Prior Treatment
• Patients who are currently receiving hormone replacement therapy (estrogen or progesterone); or are taking tamoxifen or raloxifene are not eligible. Women who have taken these medications must have stopped for at least 4 months prior to study entry.

Topical estrogen (eg, transdermal patches and vaginal estrogens) is allowed.

• Patients who are currently using hormonal contraception, should be taking it for at least 4 months prior to study entry.
• Vitamin D Use
• Patients who are taking regular vitamin D supplementation (above 400 IUs daily) and refuse or are unable to stop use are not eligible. Women who agree to stop will need to do so for at least 6 months prior to registration.
• Patients may not start vitamin D supplementation after registration (regardless of results of vitamin D testing) but they may continue vitamin D if they are already taking 400 IUs daily or less and have been taking vitamin D for at least 6 months prior to baseline mammogram.
• Patients with a history of breast cancer (including DCIS) or ovarian cancer are not eligible.
• Patients with a history of breast implants or breast reduction are not eligible.
• Patients with two or more bone fractures in the past five years are not eligible.
• Patients with a diagnosis of osteoporosis with physician recommendation for treatment of low bone mass are not eligible.
• Patients known to have hyperparathyroid disease or other serious disturbances of calcium metabolism requiring intervention in the past 5 years are not eligible.
• Patients with a history of kidney stones (unless documented not to have been a calcium stone) are not eligible.
• Patients participating in a concurrent breast cancer chemoprevention trial are not eligible.
• Required initial laboratory values - Calcium < 10.5 mg/dL