Effects of High Dose Calcitriol in Breast Cancer Patients
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Intervention: Calcitriol
Intervention description: In pill form, 45 micrograms once a week for 12 weeks
Intervention MeSH terms: Calcitriol
Phase: Phase 2
Study type: Interventional
Primary purpose: Prevention
Intervention model: Single Group Assignment
Masking: None (Open Label)
Enrollment: 12.0
Sex: Female
Minimum age: 18 Years
Maximum age: 88 Years
Healthy volunteers: No

Summary:

      This research will examine the effectiveness of calcitriol in treating bone loss in women who
      are about to begin treatment for breast cancer. Twenty-five (25) subjects are expected to
      take part in this study. The investigators don't know if bone loss in breast cancer survivors
      should be treated differently than bone loss in other women.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Must be female.

          -  Must have pathologically confirmed incident, primary invasive breast cancer.

          -  Must be awaiting surgical resection.

          -  Women of child-bearing potential (i.e. women who are pre-menopausal or not surgically
             sterile) must use acceptable contraceptive methods (abstinence, intrauterine device
             (IUD), or double barrier device) and must have a negative serum or urine pregnancy
             test within 1 week prior to beginning treatment on this trial. Contraceptive use needs
             to be continued at least 1 month after the trial has ended.

          -  Must provide informed consent.

          -  Must be willing to discontinue use of calcium and/or vitamin D supplements other than
             multivitamin supplementation.

          -  Participants must have an ionized serum calcium level within normal limits
             (1.19-1.29mmol/L) and a total corrected serum calcium of < 10.2mg/dl.

        Exclusion Criteria:

          -  Subjects with life-threatening conditions that would preclude them from breast cancer
             treatment including: chronic cardiac failure, which is unstable despite medication
             use; uncontrolled hypertension; uncontrolled diabetes mellitus; or unstable coronary
             artery disease.

          -  Patients with severe metabolic disorders, which includes phenylketonuria (PKU),
             homocystinuria, and Fabry's disease, that would preclude them from taking calcitriol.

          -  Patients with a previous history of any other cancer except non-melanomous skin cancer
             within the past 5 years.

          -  Patients with impaired renal function (CRCL < 60 mL/min) or who had kidney stones
             (calcium salt) within the past 5 years.

          -  Patients with hypercalcemia (corrected serum CA > 10.2 mg/dl) or a history of
             hypercalcemia or vitamin D toxicity.

          -  Patients currently taking calcium supplements or aluminum-based antacids must
             immediately discontinue their use if they are to enroll in the study.

          -  Patients currently taking vitamin D supplements must immediately discontinue their use
             if they are to enroll in the study.

          -  Patients with a known sensitivity to calcitriol.

          -  Women who are pregnant or lactating.

          -  Women on antiresorptive drugs (e.g. bisphosphonates) within the past year.

          -  Women currently using oral contraception.

          -  Women with malabsorptive syndromes (i.e. cystic fibrosis, chronic pancreatitis) or
             taking medications that decrease the absorption of fat soluble vitamins (i.e.
             Orlistat, Questran).

          -  Participants assigned to calcitriol who are routinely taking a multivitamin supplement
             may continue the supplement as long as the amount of vitamin D in the supplement is
             not in excess of the RDA (recommended daily allowance) of 400 IU or 10 μg. If they are
             not taking a multivitamin supplement, they will be asked to not start supplementation
             while on study.