Breast Cancer, Fracture, Osteopenia, Osteoporosis
Conditions
Brief summary
Research Question: Do Aromatase Inhibitors Decrease Intestinal Calcium Absorption? Study Design: Postmenopausal women with early stage breast cancer initiating aromatase inhibitor adjuvant therapy will participate in this two-month study. The primary study outcome is the change in intestinal calcium absorption following such therapy. Secondary outcomes are the changes in bone resorption markers and musculoskeletal signs and symptoms after initiation of therapy. We will interview women and review their medical records to determine eligibility. Eligible subjects will undergo two calcium absorption studies. The first study will determine their baseline calcium absorption, and the second study will occur after taking an aromatase inhibitor daily for at least 6 weeks. Women will present to the research unit in the early morning and receive an oral and intravenous stable calcium tracer with breakfast. Over the next 24 hours, we will collect all urine for measurement of its calcium content. During each inpatient stay, we will assess musculoskeletal symptoms by questionnaire and joint examination. Each woman will complete a four-day diet diary twice during the study.
Interventions
DRUGAromatase Inhibitor
Any aromatase inhibitor started as initial adjuvant therapy
Sponsors
University of Wisconsin, Madison
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Healthy volunteers
No
Inclusion criteria
* Women at least 5 years past menopause, defined as date of last menses or bilateral oophorectomy * Newly diagnosed breast cancer and starting an AI as initial adjuvant therapy
Exclusion criteria
* Recent, current or planned chemotherapy for breast cancer, as this may have independent effects on intestinal health, calcium homeostasis and bone turnover * Allergy or intolerance to orange juice, as one isotope is given with orange juice * Current use of over-the-counter or prescription antacids, as they may influence Ca-Ab * Intestinal conditions associated with malabsorption or low gastric acid levels including Crohn's disease, ulcerative colitis, pernicious anemia, bacterial overgrowth, celiac sprue, chronic diarrhea or use of antibiotics within the past month * Known Stage 4 or 5 Chronic Kidney Disease, defined as an estimated GFR \<30 cc/minute * Use of medications known to interfere with calcium or vitamin D metabolism, including oral steroids or anticonvulsants * Significant lymphedema precluding adequate intravenous access
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Intestinal Calcium Absorption Related to Aromatase Inhibitor Therapy | baseline and 6 weeks later | intestinal calcium absorption |
Participant flow
Recruitment details
Postmenopausal women with early stage breast cancer and planning to start aromatase inhibitor therapy.
Pre-assignment details
Participants completed a four-day food diary
Participants by arm
| Arm | Count |
|---|---|
| Group 1 | 12 |
| Total | 12 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Protocol Violation | 2 |
Baseline characteristics
| Characteristic | Group 1 |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 6 Participants |
| Age, Categorical Between 18 and 65 years | 6 Participants |
| Age Continuous | 66 years STANDARD_DEVIATION 7 |
| Region of Enrollment United States | 12 participants |
| Sex: Female, Male Female | 12 Participants |
| Sex: Female, Male Male | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 10 |
| serious Total, serious adverse events | 0 / 10 |
Outcome results
Primary
Change in Intestinal Calcium Absorption Related to Aromatase Inhibitor Therapy
intestinal calcium absorption
Time frame: baseline and 6 weeks later
Population: 12 subjects provided informed consent but two dropped and did not undergo calcium absorption study visits. 10 subjects completed all calcium absorption study visits.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Aromatase Inhibitor Therapy | Change in Intestinal Calcium Absorption Related to Aromatase Inhibitor Therapy | 16 percent calcium absorption | Standard Deviation 6 |