Bone cancer is a malignant tumor of the bone.
It may originate in the bone itself, in which case it is called primary
bone cancer. More commonly, however, it occurs as a result of cancer
spreading from elsewhere in the body. Cancer that spreads, or metastasizes,
to the bones from other parts of the body, such as the breast, lung, or
prostate, is called secondary bone cancer or metastatic
cancer, and is named for the organ or tissue in which it began.
Secondary bone cancer is far more common than primary bone cancer. The cancerous
growth replaces bone, causing pain and sometimes swelling. It also makes
the bone more likely to fracture without preceding injury.
|Cloudy X-ray appearance of osteosarcoma
Not all bone tumors are malignant. In fact, benign (noncancerous) bone tumors
are more common than malignant ones. Both malignant and benign bone tumors
may grow and compress healthy bone tissue, but benign tumors do not spread,
do not destroy bone tissue, and are rarely a threat to life.
Primary bone cancer
All forms of primary bone cancer are rare. The type that occurs most often
is osteosarcoma, which most frequently
affects the leg bones of children and young adults. Symptoms of osteosarcoma
are pain, tenderness, and swelling, typically just above or just below the
knee or in the upper arm.
Other types of primary bone cancer include chondrosarcoma
(originating from cartilage) and fibrosarcoma
(from fibrous tissue). Bone cancer can also start in the bone
marrow, as in the case of and multiple
myeloma. Ewing's sarcoma usually
occurs in bone but may also arise in soft tissue (muscle, fat, fibrous tissue,
blood vessels, or other supporting tissue).
Secondary, or metastatic, bone cancer usually occurs later in life. The
cancers that spread rapidly to bone are those of the breast,
thyroid, and kidney.
Bone metastases occur commonly in the spine, pelvis, ribs, and skull.
In secondary bone cancer, pain is usually the main symptom and is often
worse at night. Affected bone are abnormally fragile and may fracture, even
without preceding injury. Such a fracture (a pathological fracture) may
be the first indication that a person has cancer.
of primary bone cancer
Although bone cancer does not have a clearly defined cause, researchers
have identified several factors that increase the likelihood of developing
these tumors. Osteosarcoma occurs more frequently in people who have had
high-dose external radiation therapy or treatment with certain anticancer
drugs; children seem to be particularly susceptible. A small number of bone
cancers are due to heredity. For example, children who have had hereditary
retinoblastoma (an uncommon cancer of the eye) are at a higher risk of developing
osteosarcoma, particularly if they are treated with radiation. Additionally,
people who have hereditary defects of bones and people with metal implants,
which doctors sometimes use to repair fractures, are more likely to develop
osteosarcoma Ewing sarcoma is not strongly associated with any heredity
cancer syndromes, congenital childhood diseases, or previous radiation exposure.
Incidence of bone cancer
Primary bone cancer is rare. It accounts for much less than 1 percent of
all cancers. About 2,300 new cases of primary bone cancer are diagnosed
in the United States each year. Different types of bone cancer are more
likely to occur in certain populations:
- Osteosarcoma occurs most commonly between ages 10 and 19. However,
people over age 40 who have other conditions, such as Paget's
disease (a benign condition characterized by abnormal development
of new bone cells), are at increased risk of developing this cancer.
- Chondrosarcoma occurs mainly in older adults (over age 40). The risk
increases with advancing age. This disease rarely occurs in children
- Ewing's sarcomas occur most often in children and adolescents under
19 years of age. Boys are affected more often than girls. These tumors
are extremely rare in African American children.
Symptoms of bone cancer
Pain is the most common symptom of bone cancer, but not all bone cancers
cause pain. Persistent or unusual pain or swelling in or near a bone can
be caused by cancer or by other conditions. It is important to see a doctor
to determine the cause.
Diagnosis of bone cancer
To help diagnose bone cancer, the doctor asks about the patient's personal
and family medical history. The doctor also performs a physical examination
and may order laboratory and other diagnostic tests. These tests may include:
- X-rays, which can show
the location, size, and shape of a bone tumor. If X-rays suggest that
an abnormal area may be cancer, the doctor is likely to recommend special
imaging tests. Even if X-rays suggest that an abnormal area is benign,
the doctor may want to do further tests, especially if the patient is
experiencing unusual or persistent pain. Among the special imaging tests
are available are:
- A bone scan, which is a test
in which a small amount of radioactive material is injected into
a blood vessel and travels through the bloodstream; it then collects
in the bones and is detected by a scanner.
- A computed tomography
(CT or CAT) scan, which is a series of detailed pictures of
areas inside the body, taken from different angles, that are created
by a computer linked to an X-ray machine.
- A magnetic resonance
imaging (MRI) procedure, which uses a powerful magnet linked
to a computer to create detailed pictures of areas inside the body
without using X-rays.
- A positron emission
tomography (PET) scan, in which a small amount of radioactive
glucose (sugar) is injected into a vein, and a scanner is used to
make detailed, computerized pictures of areas inside the body where
the glucose is used. Because cancer cells often use more glucose
than normal cells, the pictures can be used to find cancer cells
in the body.
- An angiogram, which is an
X-ray of blood vessels.
- Biopsy (removal of a tissue sample
from the bone tumor) to determine whether cancer is present. The surgeon
may perform a needle biopsy or an incisional biopsy. During a needle
biopsy, the surgeon makes a small hole in the bone and removes a sample
of tissue from the tumor with a needle-like instrument. In an incisional
biopsy, the surgeon cuts into the tumor and removes a sample of tissue.
Biopsies are best done by an orthopedic oncologist (a doctor experienced
in the treatment of bone cancer). A pathologist (a doctor who identifies
disease by studying cells and tissues under a microscope) examines the
tissue to determine whether it is cancerous.
- Blood tests to determine the level
of an enzyme called alkaline phosphatase. A large amount of this enzyme
is present in the blood when the cells that form bone tissue are very
active – when children are growing, when a broken bone is mending,
or when a disease or tumor causes production of abnormal bone tissue.
Because high levels of alkaline phosphatase are normal in growing children
and adolescents, this test is not a completely reliable indicator of
Treatment of bone cancer
Treatment options depend on the type, size, location, and stage of the cancer,
as well as the personís age and general health. Treatment options for bone
cancer include surgery, chemotherapy, radiation therapy, and cryosurgery.
- Surgery is the usual treatment for bone cancer. The
surgeon removes the entire tumor with negative margins (no cancer cells
are found at the edge or border of the tissue removed during surgery).
The surgeon may also use special surgical techniques to minimize the
amount of healthy tissue removed with the tumor. Dramatic improvements
in surgical techniques and preoperative tumor treatment have made it
possible for most patients with bone cancer in an arm or leg to avoid
radical surgical procedures (removal of the entire limb). However, most
patients who undergo limb-sparing surgery need reconstructive surgery
to maximize limb function.
- Chemotherapy is the use of anticancer drugs to kill
cancer cells. Patients who have bone cancer usually receive a combination
of anticancer drugs. However, chemotherapy is not currently used to
- Radiation therapy, also called radiotherapy, involves
the use of high-energy X-rays to kill cancer cells. This treatment may
be used in combination with surgery. It is often used to treat chondrosarcoma,
which cannot be treated with chemotherapy, as well as Ewing sarcomas.
It may also be used for patients who refuse surgery.
- Cryosurgery is the use of liquid nitrogen to freeze
and kill cancer cells. This technique can sometimes be used instead
of conventional surgery to destroy the tumor.
Bone cancer sometimes metastasizes, particularly to the lungs, or can recur,
either at the same location or in other bones in the body. People who have
had bone cancer should see their doctor regularly and should report any
unusual symptoms right away. Follow-up varies for different types and stages
of bone cancer. Generally, patients are checked frequently by their doctor
and have regular blood tests and X-rays. People who have had bone cancer,
particularly children and adolescents, have an increased likelihood of developing
another type of cancer, such as leukemia,
later in life. Regular follow-up care ensures that changes in health are
discussed and that problems are treated as soon as possible.