What is the efficacy of exercise on bone health in patients with multiple myeloma?

Exercise Efficacy on Bone Health in Multiple Myeloma

Exercise in multiple myeloma patients shows conflicting evidence for improving bone mineral density, but combined resistance and impact exercise programs demonstrate the most promise for preserving bone health, particularly at the lumbar spine, while safely improving physical function, quality of life, and reducing fatigue. 1

Evidence for Bone-Specific Outcomes

Bone Mineral Density Effects

• Combined resistance and impact exercise showed positive effects on lumbar spine BMD in cancer survivors, though overall meta-analysis found no significant benefit at lumbar spine, femoral neck, or total hip. 1
• Recreational soccer training in men with prostate cancer on androgen deprivation therapy showed increases in bone formation markers and preserved bone mass at 12 weeks, 32 weeks, and 5 years of follow-up. 2
• Exercise alone may be insufficient to improve bone health in cancer survivors and should be combined with adequate calcium and vitamin D supplementation (>800 IU daily). 2, 1

Exercise Protocol Recommendations

Based on systematic review of 20 exercise studies in multiple myeloma, the NCCN recommends an exercise protocol incorporating aerobic, resistance, and flexibility exercises with specific precautions for bone metastases. 2

The optimal exercise prescription includes: 1

• Duration: 60+ minutes per session
• Frequency: 2-3 times per week
• Duration of program: 7+ months minimum
• Type: Multiple exercise modalities, particularly resistance combined with impact exercise

Safety and Feasibility Evidence

Recent Trial Data

A 2024 randomized controlled trial (N=100 newly diagnosed MM patients) demonstrated no significant safety concerns with a 10-week individualized exercise program, though knee extension strength declined in the intervention group while sit-to-stand test, aerobic capacity, and global quality of life improved in both groups. 3

A 2024 pilot study (N=42) showed both supervised strength training and remotely prompted walking interventions were feasible with no intervention-related serious adverse events, though adverse events mostly affected the musculoskeletal system. 4

Exercise Intensity Guidelines

Physical therapy using the Borg scale rating of 13 (somewhat hard) and limiting bone pain to Grade 1 per Common Terminology Criteria for Adverse Events v4.0 safely improved activities of daily living in MM patients with performance status 4. 5

Functional Benefits Beyond Bone Health

Physical Function Improvements

• Supervised resistance training for 6 months produced significant improvements in AM-PAC scores, timed up-and-go test, 6-minute walk test, and 30-second sit-to-stand test, with most effects sustained 6 months post-intervention. 4
• Exercise interventions led to small but statistically significant improvements in self-reported physical function among patients with hematologic malignancies (SMD 0.15; 95% CI, -0.01 to 0.32; 8 trials, N=1,329 patients). 2

Fatigue Reduction

Exercise produces moderate to large reductions in cancer-related fatigue in hematologic malignancies (SMD -0.52; 95% CI, -0.70 to -0.34). 2

Quality of Life

Among patients with hematologic malignancies, exercise showed a nonsignificant impact on QoL (SMD 0.11; 95% CI, -0.03 to 0.24; 8 studies, N=1,259 patients), though patients treated with bone marrow transplantation reported significant improvement (MD 3.38 points; 95% CI, 0.37 to 6.39; 11 studies, N=624 patients). 2

Critical Safety Considerations

Fracture Risk Assessment

Fracture risk assessment must precede exercise prescription. 1

• Lesions >2.5 cm in diameter or encompassing >50% of bone diameter create high fracture risk and require surgical stabilization before rehabilitation. 1
• Individualized assessment must account for lesion size, location in weight-bearing areas, and pain refractory to radiation. 1

Contraindications

Weight-bearing exercise should be avoided at sites with lytic lesions until appropriate imaging confirms structural integrity, and modalities increasing local blood flow (ultrasound therapy, thermotherapy, massage) should not be performed at tumor sites. 6

Clinical Implementation Algorithm

Step 1: Obtain whole-body low-dose CT to identify and characterize bone lesions. 7

Step 2: Assess fracture risk based on lesion size (>2.5 cm or >50% bone diameter = high risk). 1

Step 3: If high fracture risk exists, refer for surgical stabilization before initiating exercise. 1

Step 4: Prescribe combined resistance and impact exercise program:

• 60+ minutes per session, 2-3 times weekly, for minimum 7 months 1
• Target Borg scale 13 intensity 5
• Limit bone pain to Grade 1 per CTCAE v4.0 5

Step 5: Ensure concurrent calcium and vitamin D supplementation (>800 IU daily). 2, 1

Step 6: Monitor for musculoskeletal adverse events and adjust intensity accordingly. 4

Important Caveats

The evidence for bone density improvement specifically in MM remains limited and conflicting, with the most recent large RCT (2024) showing no significant BMD benefits. 3 However, exercise provides substantial benefits for physical function, fatigue, and quality of life without significant safety concerns when appropriately prescribed. 4, 3

Bone healing in lytic lesions is slow, with sclerosis only beginning 3-6 months after therapy initiation and taking over a year to mature, so BMD improvements may require longer intervention periods than studied to date. 1

Home-based exercise programs showed 75% adherence rates in MM patients, suggesting feasibility, though supervised programs produced more robust and sustained functional improvements. 4, 8