What is secondary bone cancer?
Bone cancer can start as a primary or secondary cancer. Secondary bone cancer refers to a cancer that has started in another part of the body and has spread (metastasised) to the bone via the bloodstream or lymph nodes. The cancer can spread to the bones in the spine, ribs and pelvis, upper arms and legs.
There are two main types of bone cancer:
- Osterolytic where the bone has become damaged.
- Osteoblastic where new bone has formed but has grown abnormally which weakens the bone.
Secondary bone cancer is more common than primary bone cancer as the bone is one of the most common sites cancer spreads to. Any type of cancer can spread to the bones but the most common are prostate, breast, lung, thyroid and myeloma.
Secondary bone cancer symptoms
The most common symptom is pain which may be a dull, persistent ache that gets worse with movement and at night. Other symptoms can include:
fractures - cancer cells can weaken the bones causing them to break more easily
high levels of calcium found in the blood (hypercalcaemia) - when the bone breaks down it releases calcium into the bloodstream and when it builds up can cause nausea and vomiting, fatigue, constipation thirst or confusion
pressure on the nerves in the spine - fractures or abnormal bone growth can press on the nerves in the spine causing back pain, tingling or numbness in the limbs, difficulty walking or muscle weakness
low levels of blood cells - secondary bone cancer can affect the bone marrow which make blood cells. You may feel tired and breathless, bruise and bleed more easily or have an increased risk of infection.
Causes of secondary bone cancer
Secondary bone cancer is always caused by a primary cancer. This is when cancer cells spread to the bone from a primary cancer such as prostate cancer.
Diagnosis of secondary bone cancer
Secondary bone cancer can be diagnosed at the same time as the primary cancer. It can also be diagnosed before the primary cancer is located.
If your doctor thinks your cancer may have spread to the bones, you may have a range of tests.
You will have a full blood count and your calcium levels will be checked.
X-ray scans will be taken of your chest and bones to check for bone damage, the formation of new bone or fractures.
You will have a small amount of radioactive dye injected into a vein that will show any abnormal changes using a scanning machine.
CT or MRI scans
Scans, including three-dimensional imagery, create pictures of your body that help to highlight any bone abnormality. The scans generally take between 30 and 90 minutes.
In a positron emission tomography (PET) scan, you will have a small amount of radioactive glucose injected into the body, which highlights any cancerous areas.
A biopsy is when some cells and tissues are removed for examination under a microscope. There are two biopsy methods.
Core needle biopsy
A thin needle is inserted under CT guidance to remove a sample of bone. This is done under local anaesthetic.
A surgeon removes a small section of the bone. This is done under general anaesthetic.
Treatment for secondary bone cancer
The aim of treatment is to control or shrink the cancer and relieve any symptoms. The type of treatment you have will depend on the type of primary cancer (if known), the treatment you have already had, how far the cancer has spread and your general health.
Some of the treatment options are outlined below.
Hormone or endocrine therapy may be used to treat prostate or breast cancer that has spread to the bone. Hormone therapy aims to lower the levels of hormones in the body or to stop hormones reaching cancer cells that need hormones to grow. It can be given as tablets or by injection.
Chemotherapy uses drugs to kill cancer cells or slow their growth. The drugs are usually given via an injection into the vein (intravenously) over several hours. You will generally have several treatment cycles with periods of rest in between. The number of sessions will vary depending on the combination of drugs prescribed.
Targeted therapy uses drugs that attack specific features of cancer cells to stop the cancer growing and spreading. Targeted therapy can only be used to treat cancers that grow in response to certain proteins in our cells. The drugs can be given orally (by mouth), as an injection under the skin or into the vein.
Immunotherapy aims to stimulate the body’s own immune system to attack the cancer most often by using checkpoint inhibitor drugs. Some cancers create ‘checkpoints’ which block the immune system so the checkpoint inhibitors allow the immune system to bypass these checkpoints. There are several checkpoint inhibitor drugs used to treat lung cancer that has spread to the bone and clinical trials are testing checkpoint immunotherapy for other types of cancer.
Radiation therapy (radiotherapy)
Radiation therapy (radiotherapy) uses targeted radiation, usually x-rays, to kill or damage cancer cells. It is also used to reduce pain in the bone.
The most common type of radiation therapy used for secondary bone cancer is external beam radiation therapy (EBRT). You may have one radiation therapy treatment, or several over a few weeks.
As cancer can weaken a bone and cause fracture, surgery may be used to insert metal rods, plates, screws, wires or pins. You may also have surgery if the cancer is pressing on the spinal cord.
You may have an injection of bone cement into the bones if the cancer is causing severe back pain or damage to the bones in the spine. This is called a vertebroplasty and helps to strengthen and stabilise the bones. It usually takes about an hour.
As secondary bone cancer is an advanced cancer your doctor may discuss palliative treatment. Palliative care aims to improve your quality of life by alleviating symptoms of cancer, without aiming to cure it. As well as slowing the spread of the cancer, palliative treatment can relieve pain and help manage other symptoms.
Depending on the type of treatment you have you may see a range of health professionals. These may include a GP, radiologist, radiation oncologist or therapist, medical oncologist or surgeon.
You may also see other allied health professionals such as nurses, social workers or counsellors.
Screening for secondary bone cancer
There is currently no national screening program for secondary bone cancer in Australia.
Preventing secondary bone cancer
As secondary bone cancer is always caused by a primary cancer there is no prevention advice specific to this disease. Having a generally healthy lifestyle including not smoking, maintaining a healthy diet and weight and limiting alcohol consumption may be protective.
Prognosis of secondary bone cancer
Prognosis refers to the likely outcome of a disease. It is not possible for any doctor to predict the exact course of your cancer. Your doctor will take into account things like whether the cancer has spread to other parts of the body, how fast it is growing and how it responds to treatment.
While secondary bone cancer cannot be cured, treatment can improve your quality of life and alleviate symptoms.
Understanding secondary bone cancer, Cancer Council Australia © 2020. Last medical review of this fact sheet: July 2020.
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