Bone metastases, also called bone metastases, is cancer that started elsewhere in the body and has spread or metastasized to the bone. Where the cancer started is called primary cancer. The metastatic cancer is also called secondary cancer or metastatic cancer. Bone metastases are therefore not the same as cancer that starts in the bone. Cancer that starts in the bone is called bone cancer. Bone metastases are much more common than primary bone cancer. The difference between primary bone cancer and bone metastases is the type of cells that make up the tumor. In bone cancer, it is the bone cells themselves that have started to divide uncontrollably. A metastasis in the bones of, for example, breast cancer or prostate cancer consists of breast cancer cells and prostate cancer cells respectively.
- Metastases in the bones
- The influence of metastatic cancer on the bone
- Osteoblastic metastases
- Osteolytic metastases
- Symptoms of bone metastases
- Examination and diagnosis
- History and physical examination
- Blood tests
- Visual art investigation
- Biopsy
- Other investigations
- Differential diagnosis
- Treatment of bone metastases
- Irradiation
- Bisphosphonates
- Denosumab
- Painkillers
- Chemotherapy
- Hormone therapy
- Surgery
- Vertebroplasty
- Life expectancy in bone metastases
Lung cancer / Source: Muratart/Shutterstock.com
Metastases in the bones
Some cancers are more likely to spread to the bones than other cancers. The following cancers are more likely to metastasize to the bones:
- breast cancer;
- prostate cancer;
- lung cancer;
- kidney cancer; and
- thyroid cancer.
Cancer can spread to any bone in the body. The most common sites of bone metastases are the vertebrae (bones of the spine), ribs, pelvis (hip bone), sternum and skull. Sometimes only part of the bone is affected. Sometimes there are metastases in several bones at the same time. Over time, cancer metastases can occur in multiple organs at the same time.
The influence of metastatic cancer on the bone
Bone is constantly being formed and broken down. This is a normal process that keeps bone healthy and strong. Metastatic cancer can disrupt this process. They can disrupt the normal balance between new and old bone and change the structure and function of the bone. Bone metastases have traditionally been classified as osteolytic and osteoblastic, but in general it can be assumed that all bone metastases have some proportion of both properties.
Osteoblastic metastases
Osteoblastic metastases develop when cancer cells invade the bone and cause too many bone cells to form. The bone becomes hardened or sclerotic. Osteoblastic metastases often occur when prostate cancer spreads to the bone.
Osteolytic metastases
Osteolytic metastases in metastatic cancer cells break down too much of the bone, making it very weak and brittle. Holes may develop in the affected bone. Osteolytic metastases often occur when breast cancer spreads to the bone.Osteolytic metastases are more common than osteoblastic metastases. Osteoblastic metastases and osteolytic metastases may occur together in the same area of the bone, such as in metastatic breast cancer.
Symptoms of bone metastases
The symptoms of bone metastases vary depending on which bones and how many bones are affected. Other health problems can cause the same symptoms as bone metastases.The most common and usually first symptom of bone metastases is pain in the bone. Bone pain can come and go, or it can be constant. It is often worse at night. The pain can occur in one area or throughout the body. It can be a dull or sharp pain. Swelling may also occur, along with bone pain.Other symptoms of bone metastases include constipation, loss of appetite, nausea, the need to urinate frequently, extreme thirst and confusion. This is caused by high levels of calcium in the blood (hypercalcemia). In addition, broken bones or fractures may occur (usually the ribs, vertebrae and long bones of the legs). Other complaints include loss of balance, a feeling of weakness and numbness in the legs and sometimes arms, and problems involving the bladder or bowel caused by pressure on the nerves or spinal cord (called spinal cord compression).
Examination and diagnosis
The following examinations can be performed to diagnose bone metastases
History and physical examination
The treating physician will physically examine you and take a history. An anamnesis is an interview with the doctor in which the patient answers questions regarding the medical history and relevant circumstances of his disease or condition. During a physical examination, the doctor focuses on possible indications of bone metastases. The doctor examines in particular areas where you experience pain or other complaints, and he pays attention to any swelling due to bone metastases.
Blood tests
Blood tests that help determine bone metastases include the following. Complete blood count (CBC) is done to assess your general health, as well as the quality of the bone marrow in the bones. There are two main types of bone marrow. Red bone marrow is the place where immature blood cells develop into red blood cells, white blood cells and platelets. Yellow bone marrow consists mainly of fat cells.Calcium and alkaline phosphatase, an enzyme found in the liver, bile ducts, intestine, bones and placenta , can be measured in the blood. A high dose may mean that damage has occurred to the bone as a result of bone metastases.Tumor markers can be measured. Tumor markers are substances, usually proteins, that your body makes in response to cancer or that are made by the cancer itself. Tumor markers can be measured in the blood, urine, cerebrospinal fluid or tissue material. The type of tumor marker depends on the type of cancer you have. For example, an increase in PSA levels (PSA stands for Prostate Specific Antigen) in the blood can indicate prostate cancer. It is often used during follow-up in men who have been treated for prostate cancer. High PSA levels may indicate that prostate cancer has returned and spread to the bones.
Visual art investigation
Imaging research is an important part of the diagnosis of bone metastases. It is common practice to perform one or more imaging tests in the event of (suspected) metastases in the bones. This includes the following studies:
- X-ray examination is usually one of the first tests to check for symptoms such as bone pain. An X-ray can also reveal fractures.
- A bone scan is used to check the entire skeleton for bone metastases, especially when there is bone pain in different places. A bone scan can often detect bone metastases earlier than an X-ray, so it is sometimes used during follow-up after cancer treatment, even when there are no symptoms of bone metastases.
- Computed tomography (CT) scan is used if both the X-rays and the bone scan show no abnormalities, but the doctor still suspects that there are metastases in the bones. It is also used to measure the size of a bone tumor. Doctors can also use a CT scan to guide them to a tumor during a needle biopsy to obtain a tissue sample.
- Magnetic resonance imaging (MRI) is used to check for spinal cord compression. It can be used when the results of a CT scan are not clear. MRI can also be used to check whether cancer has spread to the bone marrow.
- Positron emission tomography (PET) scan of the entire skeleton can be used to check for the presence of small bone metastases. It is rarely used to diagnose bone metastases, as other imaging diagnostics are usually required to monitor the results of a PET scan.
Biopsy
During a biopsy, a doctor removes a piece of tissue from the metastasis to be examined under a microscope. This is often done by the pathologist. A biopsy is sometimes necessary to diagnose bone metastases. A biopsy can be performed if it is not yet known where the cancer comes from, which is the primary cancer. A needle biopsy or surgical biopsy is usually used.A mammography is an X-ray of the breast / Source: GagliardiImages/Shutterstock.nl
Other investigations
If bone metastases are found before primary cancer is diagnosed, the doctor can find out where the cancer started by performing a number of tests:
- mammography to check for breast cancer;
- X-ray examination or CT scan of the chest to check for lung cancer; and
- transrectal ultrasound (TRUS) to check for prostate cancer.
Differential diagnosis
When the primary cancer has not yet been diagnosed, the symptoms of bone metastases resemble the following conditions:
- chondrosarcoma (a rare malignant bone tumor);
- malignant lymphoma (lymph node cancer);
- multiple myeloma or Kahler’s disease (a malignant proliferation of plasma cells in the bone marrow);
- osteomyelitis (bone inflammation);
- sarcomas of the skeleton, arising after intensive X-ray irradiation.
Treatment of bone metastases
If bone metastases have been identified, a treatment plan will be drawn up by the treating physician. This is a tailor-made plan that also takes your personal wishes and preferences into account. The treatment plan usually consists of a combination of different treatments, such as radiation and chemo. This often involves palliative treatment, intended to slow the disease or reduce symptomsRadiotherapy (irradiation) / Source: Cylonphoto/Shutterstock.com
Irradiation
Radiotherapy can be given through external beam radiation or systemic radiotherapy. External radiation can be used to combat bone pain and spinal cord compression. It is also used to prevent or heal fractures. During external radiation therapy, a machine sends the radiation through the skin. It targets a specific area where you are experiencing bone pain or that needs treatment. How long external beam radiation is used depends on the goal of treatment, the number of bones affected by cancer, and other factors.Systemic radiotherapy may be used when pain is present in many bones. It is most often used for osteoblastic metastases of prostate cancer. Systemic radiotherapy uses medicines containing radioactive substances. These medications are usually given intravenously (through a needle into a vein). They travel through the bloodstream to the cancer cells in the bone. The most common radioactive materials are strontium-89 and samarium-153. Usually only one dose of systemic radiation is given.
Bisphosphonates
Bisphosphonates are drugs that help slow the breakdown of bone. These medicines are standardly used for bone metastases. Bisphosphonates are usually given through a needle into a vein (intravenously). These medicines are usually given once a month or once every three months, but they can also be given more often. Bisphosphonates can also be given once a day as a pill by mouth (oral).
Denosumab
This medicine inhibits the breakdown of bones and makes them stronger. Denosumab is given for osteoporosis and cancer if the bones become fragile and brittle due to the tumor or metastases and are more likely to break. The Xgeva injection is administered by a doctor or nurse once every four weeks. Possible side effects include infections, such as bladder infections or bronchitis, constipation, cataracts, rash and pain or numbness in the legs. You may also experience shortness of breath or diarrhea.
Painkillers
Painkillers are commonly prescribed to relieve pain caused by bone metastases. They are often given because it often takes a while for treatments to work and then the pain decreases, or because the pain does not go away completely.
Chemotherapy
Chemotherapy can be used to shrink bone metastases and relieve symptoms such as pain. It may be an option if there are multiple areas where bone metastases are present, and the cancer is expected to be likely to respond to chemotherapy. Chemotherapy can be used for many types of metastatic cancer. The type of drug or combination of drugs depends on where the cancer started.
Hormone therapy
Hormone therapy is only used for hormone-sensitive tumors, such as metastatic breast cancer and prostate cancer. Certain cancers grow under the influence of the body’s own hormones. In some forms of breast cancer, estrogen promotes the development of metastases and in prostate cancer, testosterone promotes metastases. Hormonal treatment puts a stop to this effect of hormones on cancer cells. This form of treatment can extend the life of certain patients with bone metastases that cause hormone-dependent tumors. Moreover, the cancer process often progresses slowly, for example in the case of prostate cancer.
Surgery
Surgery may be necessary to repair a bone fracture caused by a metastasis. It can also be used to make the bone more stable to prevent it from breaking. Metal screws, pins, rods, and plates can be placed into the bone during surgery. Surgery may also be necessary to prevent or treat spinal cord compression. Most people with bone metastases must be in good general health to undergo surgery.
Vertebroplasty
Vertebroplasty strengthens painful, broken or weakened vertebrae affected by bone cancer with bone cement. The liquid bone cement is introduced into the affected bone with a hollow needle. The liquid bone cement then hardens and the bone fracture is stabilized.
Life expectancy in bone metastases
A diagnosis of advanced cancer with metastases in the bones is particularly drastic for both the patient and his immediate environment, his partner, children, etc. It can not only lead to all kinds of existential questions, but also the question of how long you have to live. soon becomes apparent. There is no way to find out exactly how long someone will live with bone metastases. This depends on many factors, including the type of cancer, the number of tumors in the bones, your overall health, the treatments used and whether these treatments are successful. For example, survival for bone metastases from prostate cancer or breast cancer is often measured in years. The chances of survival for someone with lung cancer that has spread to the bones is often measured in months. But some people live considerably longer than initially expected, while others die earlier even though they had a fairly favorable prognosis. Questions regarding life expectancy and the course of the disease process are best submitted to your treating physician. The doctor is able to give a prognosis (often with considerable caution) based on what he knows about the person, his general health situation, the stage in the disease process and the type of cancer, but a prognosis remains a statement regarding the likely course of a disease. However, the decision of the doctor and the treatment team always remains uncertain. A patient can die unexpectedly, or live an unexpectedly long time.
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