Exercise Preconditioning and Breast Cancer Cardiotoxicity

The primary aim of this study is to determine the efficacy of a novel, high-intensity aerobic interval exercise preconditioning protocol to ameliorate anthracycline-mediated cardiac and skeletal muscle toxicity in women with breast cancer undergoing de novo chemotherapy.

Research Design:

Women with breast cancer scheduled to undergo de novo chemotherapy with anthracyclines will be enrolled. Qualified patients will be randomized to either 1) a high-intensity interval exercise group, or 2) an attention-control group.

Supervised exercise training will be carried out at the Mayo Clinic Cardiac rehabilitation center in Arizona on cycle ergometers using Electrocardiogram (EKG) telemetry. Patients in the high-intensity interval exercise group will perform four, 4-min intervals at 85-90% peak heart rate (PHR), separated by 3 min at 50% PHR. Each training session will begin with a 10-minute warm-up at 50% of PHR and end with a 5-min cool down at 50% PHR.

The attention-controls will receive counseling consistent with standard of care regarding physical activity during chemotherapy. Attention-control group will receive a weekly phone call to maintain physical activity during chemotherapy and compliance will be verified using physical activity diaries and pedometers.

Treatment for each group will commence 1-week prior to chemotherapy induction. The first dose of chemotherapy will be given within 16-18 hours of the last bout of exercise. High-intensity intermittent exercise (HIIE) training will be continued throughout four, 2-week cycles of chemotherapy (total training time = 9 weeks, 3 days/week).

Inclusion criteria

• Subjects must be able to communicate meaningfully with the investigator and must be legally competent to provide written informed consent
• Subjects will have been recently diagnosed with breast cancer (stage I, II or III)
• Subjects must be scheduled by their oncologist to undergo anthracycline based chemotherapy (doxorubicin and cyclophosphamide) in the neoadjuvant/adjuvant setting

Exclusion criteria

• Unstable angina
• Myocardial infarction in the past 4 weeks
• Uncompensated heart failure
• New York Heart Association class IV symptoms
• Complex ventricular arrhythmias
• Medical orthopedic conditions precluding stationary cycling
• Medical conditions precluding neuropsychological assessment
• Symptomatic severe aortic stenosis
• Acute pulmonary embolus
• Acute myocarditis
• Untreated high-risk proliferative retinopathy
• Recent retinal hemorrhage
• Uncontrolled hypertension
• Sodium and/or Potassium ≥ Grade 2
• Pregnant Women