Bony and Spinal Metastasis

Basics

Description

  • The skeleton is one of the most common sites for metastatic cancer.
  • Bone metastasis can cause significant morbidity including pain, pathologic fractures, spinal cord compression, and hypercalcemia.
    • 80% of bony metastasis are due to breast, prostate, and lung cancers (1).

Epidemiology

Incidence

  • Breast cancer—73% bony metastasis
  • Prostate—68%
  • Thyroid—42%
  • Lung—36%
  • Renal—35%
  • Melanoma—35% (2)

Prevalence
Not well understood

  • Approximately 1.2 million new cancer diagnoses in the United States each year
  • Approximately 300,000 total cases of metastatic bone disease in the U.S. population in 2008 (3,4)

Etiology and Pathophysiology

  • Types of bone metastasis
    • Osteolytic—thyroid, non–small cell lung, kidney, multiple myeloma
    • Osteoblastic—prostate, small cell lung
    • Mixed—breast, cervical, ovarian, testicular
  • Bone—specifically the axial skeleton—is a common site for metastasis due to high blood flow in the red marrow.
  • Tumor cells exhibit adhesive molecules that allow them to bind stromal cells in the bone marrow.
  • Tumor cells produce factors that stimulate osteoblastic and/or osteoclastic activity leading to disruption in bone remodeling (2)[A].

Genetics

  • Studies are ongoing to identify specific genes involved in bony metastasis.
  • 5–10% of all cancers are hereditary.
    • Most common type is hereditary breast and ovarian cancer syndrome caused by mutations in BRCA1 or BRCA2 (4).

Risk Factors

  • Advanced disease
  • Late presentation to care
  • Large tumor size
  • Poorly differentiated tumor
  • Breast cancer is the most likely culprit for bony metastasis in the United States.

General Prevention

  • Prevention of primary tumor/early detection
  • Timely mammogram evaluations
  • Cervical Pap smears
    • Prostate-specific antigen (PSA) per guidelines—strong family history
    • Colonoscopy

Commonly Associated Conditions

  • Bone pain
  • Pathologic fractures
  • Hypercalcemia
  • Nerve compression
  • Spinal cord compression
  • Cauda equina syndrome

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