Calcitriol, Physical Activity, and Bone Health in Cancer Survivors
Condition: Breast Neoplasms; Bone and Bones
MeSH terms: Breast Neoplasms
Intervention: Calcitriol; Exercise; Multivitamin
Intervention description: Calcitriol tablet taken once per week.; Exercise consisting of progressive walking and resistance band training
Intervention MeSH terms: Calcitriol
Phase: Phase 2
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: None (Open Label)
Enrollment: 41.0
Sex: Female
Minimum age: 18 Years
Healthy volunteers: No

Summary:

      Both the calcitriol and exercise interventions are aimed at reducing fracture risk by
      maintaining proper bone density, thereby preventing osteoporotic/osteopenic conditions and
      increasing muscle mass. Both calcitriol and exercise are efficacious in maintaining proper
      bone health and muscle mass among the general population, but little research has been done
      on breast cancer patients and survivors. The combination of calcitriol and exercise, which
      function through different but similar mechanisms, could produce interactive effects in
      reducing fracture risk among breast cancer survivors.

      Hypothesis: A combination of calcitriol along with a structured home-based walking and
      progressive resistance exercise program will be efficacious in preventing bone resorption and
      in increasing bone formation among survivors of invasive breast cancer.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Must be female.

          -  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.

          -  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.

          -  Must have a functional capacity rating of ≤ 2 on the Eastern Cooperative Oncology
             Group (ECOG) performance status when assessed at baseline.

          -  Must have the approval of their treating physician (or physician's nurse practitioner
             or physician's assistant) to participate in sub-maximal physiological fitness testing
             and a low to moderate home-based walking and progressive resistance exercise program
             and to receive the 12-week supplementation of calcitriol 45 μg. Participants assigned
             to either of the calcitriol treatment arms will be instructed to stop taking calcium
             and/or vitamin D supplements.

          -  Must be less than five years from the diagnosis of breast cancer and have received
             chemotherapy, radiation therapy, and/or hormonal therapy. Chemotherapy and radiation
             therapy, if received, must have been completed prior to study enrollment. Hormonal
             therapy may be ongoing.

        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 who had a myocardial infarction within the past year.

          -  Patients with severe metabolic disorders, which includes phenylketonuria (PKU),
             homocystinuria, and Fabry's disease, that would preclude them from taking calcitriol.

          -  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 be
             willing to 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.

          -  Previously verified diagnosed of osteoporosis.

          -  Women on antiresorptive drugs (e.g. bisphosphonates) within the past year.

          -  Patients not capable of participating in an exercise intervention due to severe knee
             arthrosis or ligament/cartilage injuries of the lower extremities.

          -  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.