Evaluating the ability of exercise to suppress tumour growth in advanced breast cancer patients with osteolytic bone metastases.

This is a single-blinded (investigators blinded to group allocation), two-armed, randomised and controlled (exercise versus usual care) explorative phase 1 clinical trial which will examine the safety, feasibility and efficacy of combining spinal isometric training with a modulatory, multi-modal exercise program (M3EP-SIT) in women with advanced breast cancer and osteolytic spinal bone metastases. The exercise group (intervention arm) will receive an individually tailored and supervised three month (12 weeks) exercise program involving resistance, aerobic and flexibility exercises in addition to usual medical care. Participants assigned to the exercise arm will be required to participate in a modular, multi-modal exercise intervention with spinal isometric training (M3EP-SIT) for 12 weeks (3 months). The combined M3EP-SIT program requires participants to attend three supervised exercise sessions each week spanning 60 minutes in duration (including warm-up and cool-down). Participants will also be asked to perform the SIT program during two additional home-based exercise sessions spanning 15 minutes in duration. The M3EP component of the program will span 45 minutes, whereas the SIT component of the program will span 15 minutes (to make a 60 minute session during supervised sessions, and a 15 minute session during home-based, self-managed sessions). During the supervised exercise clinic sessions, patients will be provided with one-on-one supervision. The modular, multi-modal exercise (M3EP) component of the program will be comprised of resistance, aerobic and flexibility exercises undertaken 3 times per week in an exercise clinic setting, supervised by an accredited exercise physiologist (AEP, Exercise & Sport Science Australia). This M3EP component is designed to minimise loads on affected skeletal sites through-out the body. Exercise prescription will be modified based on the location and extent of bone metastases for all activities. Resistance exercise will be set using repetition maximums (RM). Participants will be asked to perform 10-12 RM for 3 sets per exercise to achieve moderate intensity and volume. Aerobic exercise will be set using age-predicted heart rate maximum (HRmax). Participants will engage in cardiovascular exercise using various modes including treadmill, cycling and rowing ergometers, performed at 60-85% HRmax for 20-30 minutes using heart rate monitors (Polar Electro Oy, Finland). Flexibility exercise will involve static stretching of all joints considered important for function, and for all muscles engaged during the session. All stretches will involve 2-4 sets per muscle group with a 30-60 second hold per set. The spinal isometric training (SIT) component of the program will comprise of exercises that isometrically load deep spinal muscles. These will be performed 5 times per week. Three sessions will be supervised by an accredited exercise physiologist synonymous with the M3EP component at an exercise clinic; with additional two sessions self-managed by the participant. This SIT component is designed to directly target and stimulate spinal lesion site(s) through muscular contraction, thus isometric exercises have been designed to activate the full spinal column due to the commonality of lesions in thoracic and lumbar regions; the feasibility of which has been demonstrated. The SIT program will require the participants to perform five exercises in whole and partial weight-supported prone and supine positions on the floor, whilst maintaining a neutral spine (isometrically) during gentle and dynamic accessory movements. Hip control and stationary spinal isometric exercises will first be used to ensure safe and correct technique during Week 1, prior to progressing to more challenging exercises which include less stability or dynamic accessory movements for Weeks 2 to 12. Adherence to supervised exercise sessions will be monitored and recorded by the exercise physiologists delivering the intervention. Patients will be provided with an exercise sheet for use during their twice weekly self-managed spinal isometric training sessions. Exercise sheets will be handed to the exercise physiologists at the patients next supervised session. Adherence to self-managed spinal isometric training will be subsequently be monitored and recorded by the exercise physiologist in consultation with the patient. This will be reported as a percentage of actual exercise completed versus prescribed exercise completed; as well as sessions missed as a ratio of sessions prescribed.