What are the recommended physical therapy approaches for patients with metastatic bone cancer?

Physical Therapy for Metastatic Bone Cancer

Physical therapy is safe and beneficial for patients with metastatic bone cancer when implemented after proper risk stratification using validated scoring systems, with exercise interventions demonstrating improved physical function, pain control, and quality of life without increased fracture risk. 1, 2

Mandatory Pre-Exercise Risk Stratification

Before initiating any physical therapy, fracture and neurological risk must be assessed using validated tools 1:

• Spinal lesions: Use the Spinal Instability Neoplastic Score (SINS) 1

  • SINS ≤6: Stable, safe for physical therapy 1
  • SINS 7-12: Potentially unstable, requires careful exercise modification 1
  • SINS ≥13: Unstable, absolute contraindication until surgical stabilization 1

• Long bone lesions: Use Mirels' score 1

  • Mirels' ≤7: Low risk, proceed with exercise 1
  • Mirels' 8: Moderate risk, modified exercise with caution 1
  • Mirels' ≥9: High risk, absolute contraindication until surgical stabilization 1

• Additional absolute contraindications 1:

  • Acute spinal cord compression 1
  • Severe hypercalcemia 1
  • Active infection (avoid until asymptomatic >48 hours) 3

Evidence-Based Exercise Prescription

Aerobic Exercise

Target 150 minutes per week of moderate-intensity aerobic activity 1:

• Walking, stationary cycling, and swimming are preferred modalities 1
• Start conservatively and progress gradually based on tolerance 1
• If severe fatigue (7-10 on ESAS), encourage light exercises only and avoid high-intensity activities 3

Resistance Training

Implement 2-3 sessions per week focusing on unaffected areas 1:

• Begin with isometric exercises to maintain muscle strength 1
• Use low resistance/body weight exercises in unaffected limbs 3
• For patients on hormone therapy or with osteoporosis history, use low resistance with higher repetitions 3

Location-Specific Exercise Modifications

For appendicular (limb) metastases 3:

• Avoid deep hip flexion/extension with acetabular or femoral head involvement 3
• Avoid extremes of range of motion with shoulder metastases 3
• Focus exercises on unaffected limbs 3

For axial (spine) metastases 3:

• Avoid excessive spinal flexion, extension, and torsion 3
• Avoid axial loading maneuvers 3
• Incorporate core and lower extremity strength exercises if fall risk present 3

Functional and Balance Training

Essential components for maintaining independence 1:

• Gait training with assistive devices as needed 1
• Transfer training for activities of daily living 1
• Balance exercises to prevent falls, especially with cytopenia or fall risk 3
• Single leg balance and timed up-and-go tests for assessment 3

Safety Profile and Outcomes

Exercise interventions demonstrate favorable safety profiles 4, 2:

• Studies show no increased fracture incidence compared to control groups 4
• No association between exercise and fracture risk when properly prescribed 4
• Positive outcomes include improved physical function, pain control, and quality of life 1, 5
• Rehabilitation can be safely accomplished with low risk of pathological fractures 1

Multidisciplinary Integration

Physical therapy must be coordinated within a multidisciplinary tumor board 1, 3:

• Include medical oncology, radiation oncology, orthopedic surgery, and rehabilitation specialists 1
• Screen for new bone pain and review imaging regularly 3
• Ensure no red flags for impending fracture or neurological impairment before each session 3
• Address neuropathic and musculoskeletal pain with aggressive workup 3

Adjunctive Supportive Measures

Integrate bone-targeted therapies and pain management 3:

• Bisphosphonates (zoledronic acid) or denosumab should be administered to delay skeletal-related events and reduce pain 3
• Single-fraction radiotherapy (8 Gy) is recommended for painful bone metastases 3
• Analgesic therapy following WHO guidelines should accompany physical therapy 3
• Calcium and vitamin D supplementation are essential 3

Critical Pitfalls to Avoid

Common errors that compromise patient safety 3, 5:

• Initiating exercise without validated risk assessment scores 1
• Applying heat, ultrasound, or massage directly at tumor sites (increases local blood flow) 5
• Prescribing high-impact or high-intensity exercises without proper screening 3
• Failing to modify exercises for patients with significant anemia or thrombocytopenia 3
• Neglecting to reassess bone stability with new pain or imaging changes 3

Monitoring and Progression

Continuous surveillance is required 3, 1:

• Increased monitoring of mobility and activities of daily living 3
• Use of durable medical equipment and adaptive aids as needed 3
• Regular functional capacity assessments including 6-minute walk test, 30-second sit-to-stand, and range of motion 3
• Emphasis on postural alignment, controlled movement, and proper technique throughout all exercises 2