Do Aromatase Inhibitors (AIs) Decrease Intestinal Calcium Absorption?

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.

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Key information

Conditions

Breast Cancer Bone Diseases Bone Diseases, Metabolic Breast Diseases Breast Neoplasms Fracture Fractures, Bone Metabolic Diseases Musculoskeletal Diseases Neoplasms Neoplasms by Site Nutritional and Metabolic Diseases Osteopenia Osteoporosis Skin Diseases Skin and Connective Tissue Diseases Wounds and Injuries

Sex eligibility

Female

Study type

Interventional

Phase

Phase 4

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Aromatase Inhibitor

Drug

Any aromatase inhibitor started as initial adjuvant therapy

Primary outcomes

Change in Intestinal Calcium Absorption Related to Aromatase Inhibitor Therapy

Time frame: baseline and 6 weeks later

intestinal calcium absorption

Sponsors and collaborators

Lead sponsor

University of Wisconsin, Madison

Other

Registry information

Important dates

Study start: 2009
Primary completion: 2010
Study completion: 2010
First posted: Oct 6, 2008
Registry last updated: Sep 14, 2012

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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