Bone Metastases

Bone is the third most common site of metastatic disease

Cancers most likely to metastasise to bone: 

1. Breast

2. Lung

3. Prostate

4. Thyroid 

5. Kidney

6. Bowel

Carcinomas are much more likely to metastasise to bone than sarcomas

The axial skeleton is seeded more than the appendicular skeleton, partly due to the persistence of red bone marrow in the former

The ribs, pelvis and spine are usually first affected

Batson's vertebral venous plexus allows cells to enter the vertebral circulation without first passing through the lungs. The sluggish blood flow in this plexus is more conducive to tumour survival, accounting for the high rate of prostate cancer metastasis to the spine.

Pain, pathological fractures and hypercalcemia are the major sources of morbidity with bone metastasis

Pain is the most common symptom found in 70% of patients with bone metastases. Pain is caused by stretching of the periosteum by the tumour as well as nerve stimulation in the endosteum