Effects of Aromatase Inhibitor Therapy on Muscle Function

Study Overview
=================
Brief Summary
-----------------
This is a pilot study designed to examine changes in muscle function after Aromatase Inhibitor (AI) therapy, at both the molecular and clinical level.

Official Title
-----------------
A Pilot Study Examining Molecular and Clinical Effects of Aromatase Inhibitor Therapy on Skeletal Muscle Function in Early Stage Breast Cancer

Conditions
-----------------
Breast Cancer, Breast Cancer Female

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age ≥ 18 years Post-menopausal Diagnosis of ductal carcinoma in situ (DCIS) or stage I, II, or III ER positive breast cancer Plan to initiate an AI per treating physician. Completion of all primary therapy for breast cancer, including surgery, radiation, and chemotherapy (should be completed 14 days or more prior to obtaining the baseline muscle biopsy). Ongoing HER2 targeted therapy with trastuzumab and/or pertuzumab is allowed. Ongoing neratinib therapy is not allowed. Body weight less than 350 lbs., as dictated by the weight limit for DXA (dual energy x-ray absorptiometry) scanner Must be willing to undergo muscle biopsy at baseline and after 24 weeks of AI therapy Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 at the time of study enrollment Informed consent and authorization of the release of health information must be obtained according to institutional guidelines Exclusion Criteria: Unwilling to co-enroll into the FIT core study Diagnosis of severe osteopenia or osteoporosis, defined as a bone mineral density of ≥ 2.0 standard deviations below the young adult female reference mean (T score) Diagnosis of other disorder affecting bone function or turnover, such as Paget's disease, renal osteodystrophy, parathyroid disorders, or vitamin D deficiency/osteomalacia Prior history of non-traumatic, fragility bone fracture Any muscle or neuromuscular disorder affecting muscle function, such as muscular dystrophy, myositis, or amyotrophic lateral sclerosis Any condition precluding power protocol participation (i.e. exertion on a stationary bicycle), including: New York Heart Association (NYHA) class III or IV congestive heart failure, uncontrolled angina, myocardial infarction in the prior 12 months, orthopedic surgery in the previous 6 months or plans for orthopedic surgery during the study period, chronic uncontrolled pulmonary conditions such as uncontrolled asthma (symptoms > 2 days/week) or dyspnea requiring oxygen, symptomatic peripheral vascular disease, or any other comorbidity that would interfere with the ability to complete and comply with the protocol in the opinion of the investigator Need for daily anticoagulation use Allergy to local anesthetic Locally recurrent or metastatic breast cancer a. History of prior treated malignancies, other than breast cancer, that are now stable, are in remission, and do not require active therapy, are acceptable.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in calstabin1 binding to RyR1 channels in skeletal muscle | Changes in calstabin1 binding to RyR1 channels in skeletal muscle of breast cancer patients pre and post exposure to adjuvant aromatase inhibitor therapy | through day 168 of aromatase inhibitor therapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in ryanodine receptor/calcium release channel (RyR1) oxidation in skeletal muscle | To estimate changes in RyR1 oxidation in skeletal muscle of breast cancer patients, pre- and post- exposure to adjuvant aromatase inhibitor therapy | through day 168 of aromatase inhibitor therapy | 
| Relationship between changes in RyR1 biochemistry and measures of muscle function | To explore the relationship between changes in RyR1 biochemistry and measures of muscle function, including muscle power as measured by isokinetic dynamometry | through day 168 of aromatase inhibitor therapy | 
| Relationship between markers of bone turnover and changes in RyR1 biochemistry | To explore the relationship between markers of bone turnover and changes in RyR1 biochemistry (calstabin binding to RyR1) | through day 168 of aromatase inhibitor therapy | 
| Relationship between markers of bone turnover and changes in muscle function | To explore the relationship between markers of bone turnover and changes in muscle function in terms of muscle power assessed by isokinetic dynamometry | through day 168 of aromatase inhibitor therapy | 
| Characterize the timing of development of muscle dysfunction following initiation of aromatase inhibitor therapy | To better characterize the timing of development of muscle dysfunction following initiation of aromatase inhibitor therapy, in terms muscle power measured by isokinetic dynamometry | through day 168 of aromatase inhibitor therapy | 
| Feasibility of repeated muscle biopsies in patients with early stage breast cancer initiating aromatase inhibitor therapy | 5. To describe the feasibility of repeated muscle biopsies in patients with early stage breast cancer initiating aromatase inhibitor therapy, in terms of rate of completion of baseline and follow up biopsy | through day 168 of aromatase inhibitor therapy | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Post Menopausal, ER positive, Aromatase Inhibitor Therapy, Breast Cancer