The place where a cancer starts in the body is known as the primary cancer. A malignant (cancerous) tumour is made up of millions of cancer cells. Some of these cells may break away from the primary cancer and be carried in the bloodstream to another part of the body. The cancer cells may settle in that part of the body and then form a new tumour. If this happens, it's called a secondary cancer or a metastasis.
Secondary cancer in the bone is the result of cancer cells spreading to the bone from a primary tumour somewhere else in the body. Sometimes only one area of bone is affected, but in some people the cancer spreads to a number of sites. Secondary cancers in the bone might also be called bone secondaries. Bone secondaries often develop in different bones in the body, and not all secondaries will cause symptoms or problems.
Although any type of cancer can spread to the bone, the most common types that do are cancers of the:
People who develop secondary cancer in the bone usually know that they have a primary cancer. Occasionally, a secondary bone cancer is found before a primary cancer is diagnosed. If the primary cancer can't then be found, it is called a cancer of unknown primary.
Symptoms of secondary cancer in the bone may include the following
- Bone pain - The most common symptom of secondary cancer in the bone is pain in the affected area. The pain may be a dull, persistent ache, which can occur during the day as well as at night. There may also be swelling and tenderness in the area. If you have this type of pain and it lasts for more than 1-2 weeks, let your doctor know as soon as possible. Although bone secondaries can occur in several different bones at the same time, usually only one or two areas are painful.
- Weakened bones - Sometimes if a bone is weakened by cancer it will break (fracture), even if you haven't had an accident or fall. This is known as a pathological fracture.
- Raised calcium level - When bones are affected by secondary cancer cells, increased amounts of calcium (the substance that helps to build bones) may be released into the blood. A raised level of calcium in the blood is called hypercalcaemia. It can cause symptoms such astiredness, feeling sick (nausea),constipation, thirst and confusion. However, hypercalcaemia is often discovered with a blood test before any symptoms develop.
- Pressure on the spinal cord - If secondary bone cancer affects the bones of the spine, it can put pressure on the nerves of the spinal cord.
This is called spinal cord compression and may cause symptoms such as pain, muscle weakness, and sometimes tingling and numbness of the limbs. If the lower spine is affected, it may also affect how the bowel and bladder work.
If you have weakness, pain, tingling or numbness in your legs, it's very important to tell your doctor or specialist nurse straight away so that treatment can be given as soon as possible to prevent permanent damage.
Sometimes secondary cancer in the bone can make you feel more tired than usual.
Occasionally, secondary cancer in the bone can affect the way the bone marrow works. The bone marrow is the spongy material that fills the bones and produces blood cells.
It produces different types of blood cell:
- red blood cells, which carry oxygen around the body
- white blood cells, which help to fight infection
- platelets, which help the blood to clot and prevent bleeding.
If the bone marrow is unable to produce enough red blood cells, you may become anaemic, which can make you feel tired and breathless. If you have too few white blood cells, you will be more prone to infection. And if you have a low platelet count, you may have bruising or bleeding.
*Information provided by Macmillan cancer support