What Does 'Bone Metastasis' Mean?

Bone metastasis means cancer that started somewhere else in the body has spread to bone. It is not a new, separate cancer of the bone. Breast, lung, prostate, kidney, and melanoma cancers spread to bone most often. The spine is the single most common site. Bone metastasis means the cancer has become more advanced. It is often still very treatable, though, sometimes for years.

Bone pain is often the first sign that cancer has reached a bone. It can start as an ache that is worse at night or with rest. This is unlike ordinary muscle soreness, which usually feels better with rest. Over time, it tends to become more constant. It can worsen with movement or weight-bearing. New, unexplained bone pain is always worth reporting, rather than waiting out. This matters most in someone with a cancer history.

Cancer in a bone weakens its structure. This can lead to a pathologic fracture. That is a break that happens with little or no real injury, sometimes during ordinary activity like standing up or turning over in bed. A fracture like this usually causes sudden, severe pain. It needs prompt medical attention.

Bone metastasis can release calcium from bone into the bloodstream faster than the body can manage it. This causes high blood calcium. It can bring on nausea, constipation, extreme thirst, confusion, and fatigue. This is treatable. It needs to be recognized and addressed, though, since untreated high calcium can affect the heart and kidneys.

This is the single most urgent complication of bone metastasis. It deserves its own clear warning. When a tumor in the spine presses on the spinal cord, doctors call this spinal cord compression. Warning signs include new or worsening back or neck pain. Numbness or weakness in the legs is another. So is loss of bladder or bowel control. This needs emergency treatment. It should happen within 24 hours of symptoms starting. Every hour matters. Without prompt treatment, this can cause permanent paralysis. Do not wait to see if it improves on its own. Do not wait for a routine appointment. Go to an emergency room, or call your care team's urgent line, immediately.

Treatment usually combines several approaches. Bisphosphonates and denosumab are given into a vein or as an injection under the skin. Most people need them monthly at first, and less often later if things are going well. They slow the bone breakdown cancer causes. They lower the risk of fractures and other complications. Radiation therapy can shrink a tumor in a specific bone and relieve pain. Surgery can stabilize a bone at high risk of fracture before it breaks, sometimes using metal rods or bone cement. It can also repair a bone that already broke. Pain is managed with medication tailored to how severe it is. All of this happens alongside treatment aimed at the underlying cancer itself.

• Is my bone pain likely related to my cancer, and does it need imaging?
• Am I on a bone-protecting medication like a bisphosphonate or denosumab, and should I be?
• What are the exact warning signs of spinal cord compression I should watch for, and what should I do if they appear?
• Would radiation or surgery help stabilize a specific area at risk of fracture?

• American Cancer Society — Bone Metastases
• Bone Metastasis — StatPearls, NCBI Bookshelf (NIH/NLM)