Bone Metastases Overview
are tumors that occur when cancer cells break away from the place where they
first started growing and move into bone tissue. Bone metastases are considered
a form of advanced cancer. These secondary cancers within the bone are difficult
to completely cure, but can be treated to lessen symptoms and lengthen life.
What Causes Bone Metastases?
are not bone cancer. Bone metastases are formed from cancerous cells that start
somewhere else in the body. So, bone metastases could, for instance, be cancerous
breast tissue, or another type of tissue elsewhere in the body, that has started
growing inside bone tissue.
Cancer is a
disease in which abnormal cells start dividing without control. Some tumors can
have cells break off and move around the body. Most of these shed cells die
off, but some live on in new tissue and create a metastatic tumor. These metastases
can remain hidden, even when the original tumor is gone and the patient is
unclear why certain tumors become metastatic, and others do not. In certain
types of cancer, such as advanced breast cancer or advanced prostate cancer, up
to 70 percent of patients develop bone metastases (Roodman, 2004).
common cancers that result in bone metastases include:
- breast cancer
- prostate cancer
- lung cancer
- kidney cancer
- thyroid cancer
common (but not only) locations for bone metastases include:
- pelvis (hips)
- long bones of the leg
- upper arms
metastases are common in many cancer patients. Unfortunately, bone metastases can
result in severe pain and neurological impairment due to changes in bone
structure. Other symptoms of bone metastases can include:
- fragile bones
- high levels of calcium in the blood
(which may cause nausea, confusion)
- loss of urinary or bowel control
- weakness in the legs
- anemia due to the loss of bone
be severely damaged by metastatic cancer. Metastatic tumors can destroy surrounding
bone tissue, causing “osteolytic bone destruction.” Osteolytic damage occurs
most often from tumors that originate in the colon, kidney, lung or thyroid. Other
damage can result when new bone is formed due to chemicals released by the
tumor, and this new bone may be weak and deformed. This is osteoblastic (bone
formation) damage, and is seen in cancers that start life as prostate, bladder,
or stomach cells. Some cancers, like breast cancer, can create both osteolytic
and osteoblastic damage.
osteoblastic and osteolytic damage can result in “pathological” bone fractures.
These bones break not from a fall or pressure, but during everyday activities. Bone
damage in the bones of the spine can also affect the nerves of the spinal cord,
causing neurological problems.
How Are Bone Metastases
full medical history and physical exam, including a discussion of any past incidence
of cancer, tests will be performed. X-rays will be taken of the affected bone.
Bone scans may be ordered to examine more bones to see if they are affected.
Computed tomography (CT) scans and magnetic resonance imaging (MRI) may be done
in some cases. Blood tests may also be done. If there is some question as to
whether the affected bone is the result of a bone metastasis or a primary bone
cancer, a biopsy may be performed, in which a small amount of the tumor is
removed and thoroughly examined by a pathologist.
What Treatments Are
of metastases often depends on the location and the source tumor cells.
Treatments can include radiation, medication, and surgery.
therapy is often used to slow the growth of a bone metastasis. There are
multiple types of radiation therapy, including:
- Local field radiation: This is directed at tumor and nearby tissue, and can result
in complete pain relief in 50-60 percent of cases (University of Connecticut).
- Hemi-body radiation: This is directed at a large part of the body, and is used if there are
multiple bone metastases.
- Radioisotope therapy: This involves injection of radioactive medication through a vein.
are a key part of therapy for patients with bone metastases, and may include
one or more of the following:
- bone-building medications (bisphosphonates help reduce bone damage)
- chemotherapy to
kill tumor cells and reduce tumor size
- hormone therapy (certain cancers like breast cancer and prostate cancer may be slowed by
- pain medications
be necessary when bones have fractured or will soon fracture. Tumors may be
removed during surgery. Fixation devices may be attached directly to
surrounding bone. Bone cement may be used for reinforcing bone structure.
freezing cancer cells with a probe (radiofrequency ablation or cryoablation) can
also reduce tumor size.
these treatment methods have complications and risks. Each patient will have a
unique treatment for their specific cancer and work with a variety of doctors
to tailor their care.
What Is the Prognosis for
metastases occur in advanced cancer. Often it is not possible for all cancer
cells to be removed and the patient declared cancer-free. Treatments available
may reduce the size and slow the growth of metastases so that pain and other
symptoms can be reduced, and a patient can live longer.