Vitamin D in Postmenopausal Women at High Risk for Breast Cancer
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Intervention: Cholecalciferol; Placebo capsule
Intervention description: Cholecalciferol is a vitamin D3. Vitamin D is important for the absorption of calcium from the stomach and for the functioning of calcium in the body. Cholecalciferol is used to treat or prevent many conditions caused by a lack of vitamin D.
Cholecalciferol will be available in gel capsule form at 10,000 IU (0.25 mg cholecalciferol) each.; Matching placebo capsules
Intervention MeSH terms: Vitamin D; Cholecalciferol
Phase: Phase 2
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 20.0
Sex: Female
Minimum age: 21 Years
Healthy volunteers: Accepts Healthy Volunteers
Keywords: breast cancer chemoprevention; vitamin D; breast density

Summary:

      This is a phase II study which will enroll 20 postmenopausal women who are at high risk for
      breast cancer development. The goal is to determine whether a one-year intervention of
      high-dose vitamin D at 2 different doses (20,000 IU weekly or 30,000 IU weekly) will increase
      circulating blood levels of vitamin D and to obtain preliminary data on the biologic effects
      of vitamin D for breast cancer prevention.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Elevated risk of breast cancer defined as having at least one of the following: (1)
             Predicted 5-year modified Gail model risk of 1.67% or greater, (2) Lobular carcinoma
             in situ, (3) Known BRCA1 or BRCA2 deleterious mutation carrier, (4) Prior history of
             ductal carcinoma in situ, if no current tamoxifen use or prior radiation to the
             contralateral breast.

          -  Age 21 years or older.

          -  Postmenopausal defined as > 6 months since the last menstrual period, prior bilateral
             oophorectomy, or serum follicle-stimulating hormone (FSH)/luteinizing hormone (LH)
             values consistent with institutional normal values for the postmenopausal state.

          -  Baseline mammographic density ≥25% as assessed qualitatively by the mammographer
             (25-50% = "scattered fibroglandular densities"; >50-75% = "heterogeneously dense
             breasts"; >75% = "extremely dense breasts").

          -  Baseline serum 25-hydroxyvitamin D <32 ng/ml.

          -  Normal breast exam and mammogram (Breast Imaging Reporting and Data System (BIRADS)
             score of 1 or 2) or abnormal breast imaging with a benign breast biopsy without
             evidence of cancer. Normal baseline breast magnetic resonance imaging (MRI) (BIRADS
             score of 1, 2, or 3).

          -  Prior tamoxifen or raloxifene use is allowed provided treatment is discontinued at
             least 28 days prior to enrollment.

          -  At least one breast available for imaging. No bilateral breast implants.

          -  Willingness to not take vitamin D supplements during the one year intervention, but up
             to 1000mg of calcium supplementation is allowed.

          -  Normal serum calcium.

          -  Adequate renal and hepatic function: serum creatinine, bilirubin, aspartate
             aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase < 2.0
             x the institutional upper limit of normal (IULN).

          -  Performance status of 0 or 1.

        Exclusion Criteria:

          -  Other prior malignancy. The following is allowed: adequately treated basal cell or
             squamous cell skin cancer, in situ cervical cancer, adequately treated stage I or II
             cancer from which the participant is currently in complete remission, or any other
             cancer (including breast cancer) for which the participant has been disease-free for 5
             years.

          -  History of kidney stones.

          -  Hypersensitivity reactions to vitamin D.

          -  On estrogen replacement therapy.

          -  Significant medical or psychiatric condition that would preclude study completion.