Effects of Exercise in Patients With Metastatic Breast Cancer

The EFFECT study is a multicentre, randomised controlled trial. The intervention group will participate in a 9-month exercise intervention. The exercise program will start with a 6-month period, where patients participate in a supervised multimodal exercise program twice a week supplemented with unsupervised exercises. The multimodal exercise program comprises aerobic-, resistance- and balance components. After completing the initial six-month period, one supervised session will be replaced by one unsupervised session until month nine.

Unsupervised exercises will be supported by an activity tracker (FitBit) and an exercise App specifically designed for the EFFECT trial. Patients randomized to the control group will also receive an activity tracker (like the intervention group). The investigators will advice control patients to avoid inactivity and be as physically active as current abilities and conditions allow, with the aim to progress towards being physically active for 150min/week in line with the current exercise guidelines.

Inclusion criteria

• Diagnosis of breast cancer stage IV
• ECOG (Eastern Cooperative Oncology Group scale) performance status ≤ 2
• Able and willing to perform the exercise program and wear the activity tracker

Exclusion criteria

• A potential subject who meets any of the following criteria is not eligible for enrolment into this study:

• Unstable bone metastases inducing skeletal fragility as determined by the treating clinician
• Untreated symptomatic known brain metastasis
• Estimated life expectancy < 6 months as determined by the treating clinician
• Serious active infection
• Too physically active (i.e. >210 minutes/week of moderate-to-vigorous intentional exercise
• Severe neurologic or cardiac impairment according ACSM criteria
• Uncontrolled severe respiratory insufficiency as determined by the treating clinician or if the patient is dependent on oxygen suppletion in rest or during exercise
• Uncontrolled severe pain
• Any other contraindications for exercise as determined by the treating physician
• Any circumstances that would impede adherence to study requirements or ability to give informed consent, as determined by the treating clinician
• Pregnancy