What causes bone metastases?

A primary cancer can release cells into the bloodstream or lymphatic system. Some of these cells reach bone, settle in its marrow-rich environment and alter the balance between bone breakdown and repair. This can weaken bone, cause pain, or release minerals into the blood. Breast cancer, lung cancer and prostate cancer are among the cancers that can spread to bone. Bone metastases are different from a cancer that starts in bone; they retain features of the original cancer.

Tell your cancer team about persistent or new bone pain, pain that wakes you, reduced movement, or a change in strength. Assessment may include an examination and imaging, with blood tests when needed. Treatment is chosen according to the primary cancer, the bones involved, symptoms and overall health. Ask how to protect mobility and reduce the chance of a fracture; avoid high-impact activity until a clinician has assessed a painful or weakened area.

Seek emergency care for sudden severe bone pain, inability to use an arm or leg, loss of bladder or bowel control, numbness or weakness in both legs, or new difficulty walking. These symptoms can signal a fracture or pressure on the spinal cord and need rapid assessment.

Which primary cancer is affecting the bone? Which scan is appropriate? Is a bone at risk of fracture? What symptoms could indicate spinal cord pressure, and which activities are safe?