Causes of Bone Pain
Bone pain is most commonly caused by metastatic cancer, especially from breast, prostate, and lung primary tumors, which have a high affinity for bone metastasis. 1
Cancer-Related Bone Pain
Metastatic Bone Disease
- Bone metastases are especially prevalent in advanced breast (70%), prostate (85%), lung (40%), and kidney (40%) cancers, as well as multiple myeloma (95%) 1
- Metastatic bone disease causes significant morbidity through pain, impaired mobility, pathological fractures, spinal cord compression, and hypercalcemia 1
- Pain from bone metastases tends to be most prominent with movement and can be debilitating 1
- Bone metastases typically affect the axial skeleton (spine, pelvis, ribs) more than the appendicular skeleton, though lesions in the proximal femur and humerus are also common 2
Mechanisms of Cancer-Induced Bone Pain
- Cancer-induced bone pain involves components of both inflammatory and neuropathic pain but also exhibits unique elements 3
- Osteolytic damage is mediated largely by stimulation of osteoclasts via tumor-derived cytokines 1
- Cancer cells home to the hematopoietic stem cell niches in bone and may remain dormant before progressing to overt metastases 1
Non-Cancer Causes of Bone Pain
Paget's Disease of Bone
- Characterized by chronic, focal areas of bone destruction with concurrent excessive bone repair 2
- Pain in Paget's disease can result from:
- Other manifestations include increased serum alkaline phosphatase levels and urine hydroxyproline excretion 2
Other Causes
- Osteoporosis 1
- Degenerative joint disease 1
- Cancer treatment-induced bone loss 1
- Pathologic fractures 1
Diagnosis of Bone Pain
Imaging Studies
- Isotope bone scan is sensitive for detecting skeletal pathology but provides limited information about its nature 1
- CT and MRI provide detailed structural information on skeletal damage 1
- PET provides functional information that may aid in diagnosis 1
- Plain radiographs help identify impending fractures 1
Laboratory Tests
- Evaluation should include calcium, phosphate, 25-hydroxyvitamin D, parathyroid hormone, alkaline phosphatase, and creatinine clearance 1
- Biochemical markers of bone metabolism may provide information on prognosis and response to bone-specific treatments 1
Management of Bone Pain
Pharmacological Approaches
- Bone-modifying agents (bisphosphonates and denosumab) have an analgesic effect on metastatic bone pain 1
- NSAIDs and acetaminophen may improve bone pain control when combined with opioid analgesics 1
- Topical diclofenac gel can provide relief for localized bone pain with minimal systemic effects 5
- Opioids are widely used in the treatment of bone pain but may be only partially effective 6
Interventional Approaches
- Radiation therapy is effective for painful bone metastases 1
- Surgical interventions (e.g., vertebroplasty/kyphoplasty) may provide greater likelihood of return to ambulatory status than radiation alone in some situations 1
- Consultation with an interventional pain specialist is recommended to determine optimal management strategy for vertebral augmentation 1
Supportive Care
- Daily supplemental calcium and vitamin D are strongly recommended for patients with bone metastases 1
- Optimal pain management is essential, especially in patients with marginal performance status 1
Special Considerations
- Bone pain assessment should be part of regular follow-up for patients with cancer, with imaging tests performed every 6-16 weeks during systemic therapy 1
- Identification of patients with impending fractures and referral to an orthopedic specialist for stabilization before fracture occurs is important for optimal pain management 1
- The analgesic effects of bone-modifying agents are modest, and therefore these agents should not be used as primary therapy for bone pain 1