Causes of secondary bone cancer
The cause of a secondary cancer in the bone is always a primary cancer somewhere else in the body.
Symptoms of secondary bone cancer
The most common symptom of secondary bone cancer is pain in the affected area. The pain may be a dull, persistent ache that often gets worse at night when the muscles are relaxed. There may also be swelling and tenderness in the area.
If you experience this type of pain and it lasts for more than one to two weeks, its best to 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.
Sometimes if a bone is weakened by cancer it will break (fracture), even if you have not 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 as tiredness, feeling sick (nausea), constipation, thirst and confusion.
However, in many people hypercalcaemia is 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 in 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 the legs it is very important to let your doctor know as soon as possible so that treatment can be given 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 that the bone marrow works. The bone marrow is the spongy material that fills the bones and produces blood cells. The different types of blood cells are:
red cells, which carry oxygen around the body
white 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 blood cells you may become anaemic, and be more likely to get infections or to have bruising or bleeding.
How secondary bone cancer is diagnosed
Your doctor is likely to arrange a number of tests for you if they think its possible that your cancer has spread to the bones.
Waiting to have tests, and waiting for the results, will be a worrying time for you and the people close to you. You may worry that the cancer has come back or spread, but without the results of the tests you cannot know for sure. In this situation you may find yourself torn between believing there is some other cause for your symptoms and thinking the worst.
Often the uncertainty is the hardest part. It can sometimes be easier to cope once the results of the tests are known. If the tests show that that you have secondary bone cancer, this can come as a huge shock. You may like to talk to your healthcare staff at the hospital, or a support organisation.
A blood test may be done to check your general health and the level of calcium in your blood.
You will probably have a chest x ray to see if there are any signs of cancer in the lungs.
This is a simple x ray that can show up certain changes in the bone and may show that a secondary bone cancer is present. A cancer of the bone may not always show up on a bone x ray though.
This is a more sensitive test than a simple x ray and shows up any abnormal areas of bone more clearly. A small amount of a mildly radioactive substance is injected into a vein, usually in your arm. Abnormal bone absorbs more radioactivity than normal bone, so these areas are highlighted and picked up by the scanner as hot spots. You will probably have to wait 23 hours between having the injection and the scan itself, so you may like to take a magazine or book with you to pass the time. The level of radioactivity used in the scan is very small and does not cause any harm to your body.
Even if an abnormality is detected on the bone scan, it is not always clear whether it is caused by cancer or by another condition such as arthritis. Sometimes a CT or MRI scan may help the doctors to decide whether the changes seen on a bone scan are caused by secondary bone cancer or another condition.
A CT (computerised tomography) scan takes a series of x rays, which build up a three-dimensional (3D) picture of the inside of the body. The scan is painless but takes from 1030 minutes.
Some people may be asked not to eat or drink for a few hours before the scan. Most people who have a CT scan are given a particular drink or injection of a dye just before the scan, to allow certain areas to be seen more clearly. Sometimes, both a drink and an injection may be given.
This may make you feel hot all over for a few minutes. If you are allergic to iodine or have asthma, you could have a more serious reaction to the injection. You should tell your doctor beforehand as you can usually still have the injection, but may need to take steroids for the day before and on the day of the scan.
You will probably be able to go home as soon as the scan is over.
An MRI (magnetic resonance imaging) scan is similar to a CT scan, but uses magnetic fields instead of x-rays to build up a series of cross-sectional pictures of the body. During the test you will be asked to lie very still on a couch inside a metal cylinder that is open at both ends. The whole test may take up to an hour and is painless although the machine is very noisy. You will be given earplugs or headphones to wear.
The cylinder is a very powerful magnet, so before going into the room you should remove all metal belongings. You should also tell your doctor if you have ever worked with metal or in the metal industry or if you have any metal inside your body (for example, a cardiac monitor, pacemaker, surgical clips, or bone pins). You may not be able to have an MRI because of the magnetic fields. Some people are given an injection of dye into a vein in the arm, but this usually does not cause any discomfort.
You may feel claustrophobic inside the cylinder, but you may be able to take someone with you into the room to keep you company. It may also help to mention to the staff beforehand if you do not like enclosed spaces. They can then offer extra support during your test.
A PET (positron emission tomography) scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. Before the scan, a very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. Areas of cancer are usually more active than surrounding tissue and show up on the scan.
This is a newer type of scan and you might have to travel to a specialist centre to have one. PET scans are not often needed, but you can discuss with your doctor whether one would be useful.
Very occasionally after scans, the doctors may still not be certain of the cause of the abnormality in the bone, and you may need to have a small sample of cells taken from the affected area of bone (a biopsy). A biopsy can be carried out in either of the following ways:
This test involves taking a sample of bone and examining it to see if it contains cancer cells. A local anaesthetic is injected to numb the area before the sample is taken. A needle is then passed through the skin into the bone and a small piece of the bone is taken. This part of the test can be painful. If you are feeling very anxious, you may be given an injection of a sedative to help you relax. The bone sample is examined under a microscope.
The test does not take very long and you may have it as an outpatient. If the sample is taken from your back, you may need to stay in hospital overnight. You may have to wait about 1014 days for the results of the needle biopsy. You are likely to be sore for a few days after the test, so your doctor may prescribe painkillers for you.
For this test, a small piece of bone is removed while you are under a general anaesthetic. Bone is extremely hard, and the piece that has been removed has to be softened so that it can be examined under a microscope. The softening process takes several days and because of this you may have to wait 1014 days for the results of the biopsy.
If a secondary bone cancer is found before the primary cancer
If a secondary cancer in the bone is found before a primary cancer is diagnosed, your doctor may arrange for you to have tests to find where the primary cancer is in your body. For example, your doctor may ask you to have:
a mammogram to look for primary cancer in the breast
a chest x ray and CT scan to check for lung cancer
a CT or ultrasound scan of the abdomen and pelvis to look for a kidney cancer
a prostate ultrasound and a blood sample to check for prostate cancer.
Your doctor, together with other medical staff, will look at the results of all your tests before a firm diagnosis can be made. This may take some days or possibly a few weeks. The waiting period may be a worrying time for you, but it is important that an accurate diagnosis is made. While you are waiting for your test results, you may find it helpful to have the support of a relative, a close friend or a support organisation.